U.S. patent application number 11/423373 was filed with the patent office on 2007-03-29 for disc drive system and methods for use with bio-discs.
Invention is credited to Kevin Robert McIntyre, Mark Oscar Worthington.
Application Number | 20070070848 11/423373 |
Document ID | / |
Family ID | 27400046 |
Filed Date | 2007-03-29 |
United States Patent
Application |
20070070848 |
Kind Code |
A1 |
Worthington; Mark Oscar ; et
al. |
March 29, 2007 |
DISC DRIVE SYSTEM AND METHODS FOR USE WITH BIO-DISCS
Abstract
An optical disc drive for reading encoded information, such as
on a CD, CD-R, or DVD, is modified to read biological or chemical
investigational features from a disc. The modifications can include
software changes or the addition of hardware desirably without the
need to modify the disc drive electronics.
Inventors: |
Worthington; Mark Oscar;
(Irvine, CA) ; McIntyre; Kevin Robert; (Irvine,
CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
27400046 |
Appl. No.: |
11/423373 |
Filed: |
June 9, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
10008156 |
Nov 9, 2001 |
7061594 |
|
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11423373 |
Jun 9, 2006 |
|
|
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60247465 |
Nov 9, 2000 |
|
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60293093 |
May 22, 2001 |
|
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60260761 |
Jan 11, 2001 |
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Current U.S.
Class: |
369/53.22 ;
G9B/19; G9B/19.001 |
Current CPC
Class: |
B01J 2219/0074 20130101;
G11B 19/00 20130101; B01J 2219/0061 20130101; B01J 2219/00637
20130101; B01J 2219/00689 20130101; G01N 35/00069 20130101; B01J
2219/00536 20130101; B01J 2219/005 20130101; B01J 2219/00659
20130101; C40B 70/00 20130101; B01J 2219/00585 20130101; G11B 19/02
20130101; B01J 2219/00648 20130101; B01J 2219/0072 20130101; B01J
2219/0063 20130101; B01J 2219/00605 20130101; B01J 2219/00596
20130101; B01J 2219/00702 20130101; B01J 2219/0054 20130101; G11B
7/0037 20130101; B01J 2219/00621 20130101 |
Class at
Publication: |
369/053.22 |
International
Class: |
G11B 7/00 20060101
G11B007/00 |
Claims
1. In an optical disc drive system having a light source, a
detector for detecting reflected light and providing a signal, a
signal processing system coupled to the detector for receiving the
signal from the detector and providing an output that can be used
to provide a representation of the encoded data, a method
comprising modifying an operational optical disc drive with
functionality to enable the detection of investigational features
on a disc without altering the hardware of the operational disc
drive and without altering the ability of the disc drive to read
data encoded on the disc.
2. The method of claim 1, wherein the signal processing system in
the optical disc drive has a digital signal processor (DSP) with an
analog to digital converter (ADC) for receiving an analog signal
detected by the detector and providing a digital signal, a
demodulator and decoder block for receiving the digital signal and
providing an decoded and demodulated signal, and an error detection
and correction block for detecting and correcting errors in the
decoded and demodulated signal, and providing a signal to be output
from the DSP at an output lead, the modifying including programming
the DSP so that the digital signal from the ADC is provided to the
output lead without being demodulated and decoded.
3. The method of claim 2, wherein the detector includes a plurality
of detector elements, the analog signal being provided to the DSP
is a signal summed from at least some of the detector elements.
4. The method of claim 3, wherein analog data signals from the
detector elements are combined to produce a tracking error signal
and a focusing error signal.
5. The method of claim 2, wherein the analog signal includes
signals indicative of investigational features on the optical
disc.
6. The method of claim 5, comprising characterizing the
investigational features based on the digital signals.
7. The method of claim 2, wherein programming includes causing the
ADC digital signal to bypass the demodulation and decode block.
8. The method of claim 2, wherein the programming includes altering
parameters to the demodulation/decode block such that the ADC
digital is unprocessed by the demodulation/decode block.
9. The method of claim 1, wherein the optical disc being read has
an investigational feature at a location where a beam of light not
blocked by the investigational feature is transmitted through the
disc, the transmitted light thereby including information about the
investigational feature, the modifying including adding a second
detector for receiving the transmitted light and providing a second
detector signal representative of the investigational feature.
10. The method of claim 9, wherein the second detector includes a
plurality of detection elements.
11. The method of claim 9, further comprising adding circuitry for
processing the second detector signal.
12. The method of claim 9, further comprising providing an analog
to digital converter (ADC) to digitize the second detector
signal.
13. The method of claim 12, wherein the complete and operational
disc drive has a housing, the second detector being located within
the housing and the ADC is outside the housing.
14. The method of claim 11, wherein the complete and operational
disc drive had a housing, the second detector being located within
the housing, the modifying further includes providing processing
circuitry for processing the second detector signal within the
housing.
15. The method of claim 1, wherein the modifying includes adding a
second light source and a second detector for detecting information
from the disc separate from the encoded information.
16. The method of claim 15, wherein the information form the disc
separate from the encoded information includes a bar code.
17. The method of claim 15, wherein the information from the disc
separate from the encoded information includes a mark on the disc
that has information indicative of the location of an
investigational feature.
18. The method of claim 1, wherein the modifying includes altering
firmware to read a signal indicative of a characteristic of an
investigational feature.
19. An optical disc drive system for reading a disc having encoded
operational data, comprising: a light source; a detector for
detecting reflected light and providing a signal; a signal
processing system coupled to the detector for receiving the signal
from the detector and providing an output that can be used to
provide a representation of the encoded data, the signal processing
system including a digital signal processor (DSP) adapted to
process a signal of an investigational feature.
20. The system of claim 19, wherein the DSP includes: an analog to
digital converter (ADC) for receiving an analog signal detected by
the detector and providing a digital signal; a demodulator and
decoder block for receiving the digital signal and providing a
decoded and demodulated signal; and an error detection and
correction block for detecting and correcting errors in the decoded
and demodulated signal, and providing a signal to be output from
the DSP at an output lead; the DSP being programmed so that the
digital signal from the ADC is provided to the output lead without
being demodulated and decoded.
21. The method of claim 20, wherein the detector includes a
plurality of detector elements, the analog signal provided to the
DSP being a signal summed from at least some of the detector
elements.
22. The method of claim 21, wherein analog data signals from the
detector elements are combined to produce a tracking error signal
and a focusing error signal.
23. The method of claim 19, wherein the analog signal includes
signals indicative of investigational features on the optical
disc.
24. The method of claim 23, comprising characterizing the
investigational features based on the digital signals.
25. The method of claim 20, wherein programming causes the ADC
digital signal to bypass the demodulation and decode block.
26. The method of claim 20, wherein the programming controls
parameters to the demodulation/decode block such that the ADC
digital is unprocessed by the demodulation/decode block.
27. A method for use by an optical disc drive for general use and
not as a dedicated disc analyzer including providing to a user the
ability to controllably disable an automatic gain control
function.
28. A method for use by an optical disc drive for general use and
not as a dedicated disc analyzer including providing to a user the
ability to monitor a focusing offset signal.
29. (canceled)
30. (canceled)
31. (canceled)
32. (canceled)
33. (canceled)
34. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S.
application Ser. No. 10/008,156, filed Nov. 9, 2001 and claims
priority from U.S. provisional applications 60/247,465, filed Nov.
9, 2000; 60/260,761, filed Jan. 11, 2001; and 60/293,093, filed May
22, 2001. Each of these priority documents is expressly
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to the use of optical discs
and optical disc readers for performing assays.
[0003] Commonly assigned, U.S. patent applications Ser. No.
09/183,842, filed Oct. 30, 1998; Ser. No. 09/311,329, filed May 11,
1999; and Ser. No. 09/421,870, filed Oct. 26, 1999, are each hereby
incorporated by reference. These applications describe methods and
apparatus for detecting operational structures, such as pits or dye
regions, and investigational features, such as biological material,
on one or more surfaces of an optical disc assembly.
[0004] Deriving information about operational structures and
investigational features using a single optical path may require
complex manipulation of the information processed in the optical
path, as discussed, for example, in co-pending commonly-assigned
U.S. patent application Ser. No. 09/378,878, which is hereby
incorporated by reference in its entirety.
SUMMARY OF THE INVENTION
[0005] The present invention provides methods and apparatus for
detecting investigational features on an optical disc. The
structures, features, characteristics, and attributes which can be
investigated according to the present invention with
investigational features may include biological, chemical, or
organic specimens, test samples, investigational objects such as
organic material, and similar test objects or target samples. Such
structures, features, and attributes may be imaged on an output
monitor. The investigational features may also include specific
chemical reactions and the products and by-products resulting
therefrom, such as, any one of a variety of different colorimetric
assays. These features can be used for medical assays, but also for
other uses, such as to detect chemicals or detect water purity.
[0006] An optical bio-disc may be implemented on an optical disc
including a format such as CD, CD-R, CD-RW, DVD, DVD-R, DVD-RW, or
a modified version thereof The bio-disc may include encoded
information for performing, controlling, and post-processing the
test or assay. For example, such encoded information may be
directed to controlling the rotation rate of the disc. Depending on
the test, assay, or investigational protocol, the rotation rate may
be variable with intervening or consecutive sessions of
acceleration, constant speed, and deceleration. These sessions may
be closely controlled both as to speed and time of rotation to
provide, for example, mixing, agitation, or separation of fluids
and suspensions with agents, reagents or antibodies. A disc drive
assembly is employed to rotate the disc, read and process any
encoded information stored on the disc, and analyze the liquid,
chemical, biological, or biochemical component or other
investigational feature in an assay zone of the disc. The disc
drive assembly may also be utilized to write information to the
bio-disc either before or after the material in the assay zone is
analyzed by the read beam of the drive.
[0007] In one embodiment, one or more signal processing circuits
within an optical disc drive are programmably configured to
function as an analog to digital converter (ADC), and preferably to
bypass demodulator and error correction circuitry. The ADC is used
to detect an electronic profile associated with investigational
features on or in the optical disc. The profiles may be used to
determine relative size, composition, and location of the detected
structures. The disc drive may optionally be programmably returned
to its standard operating configuration. The ADC functionality may
be incorporated in a digital signal processor (DSP) which is
programmable without hardware change. The programming may cause the
signal from the ADC to be provided to an output lead of the DSP, or
the programming could cause the signal to essentially pass through
other components from the ADC without being substantially
altered.
[0008] The present application relates to other ways in which a
conventional optical disc drive having a light source, a detector
for detecting light reflected from the light source to the disc,
and various signal processing circuitry may be used to obtain
information about an investigational feature.
[0009] In another embodiment, the disc is made using a
semi-reflective (and semi-transparent) material such that light can
be reflected and detected by the disc drives normal detector.
Additional functionality can be provided over the disc to detect
transmitted light. These additional components can use a detector
with one or more detecting elements, a pre-amplifier, automatic
gain control, an analog switch for combining signals from multiple
elements (if provided), and additional processing circuitry
including an ADC, microprocessor, and/or threshold detector and
event counter. These items are preferably provided on a board that
can be added to the device through retrofitting such that a
conventional, commercial disc drive, preferably of the type that
can be provided into a compartment of a personal computer is
modified without changing the basic functionality of the disc
drive. In the preferred embodiment, no wires need be attached to
the reflective light source, detector, or processing circuitry,
although some connections could be made if desired, for example, to
compare signals received by the top and bottom detectors.
[0010] In the case of the semi-reflective, semi-transparent disc,
the encoded information is provided as it conventionally is in a
CD, CD/R, or DVD, while investigational features are provided at
target zones where the encoded information is removed, allowing
more transmission with less reflection. The system preferably
includes a form of triggering that can either be hardware or
software based. A triggering signal indicates that an
investigational feature is being observed. This can arise from a
physical trigger mark located on the disc that identifies a radius
along which there are target zones with investigational features,
or it can include encoded data identifying where a target zone is
located. In the case of a hardware trigger, the signal from the
triggering sensor can be provided to an ADC or other processing
circuitry that causes that circuitry to process the current
detector signal; in the case of software triggering, the software
controls the ADC or other processing circuitry. The data collected
under software control is subsequently searched through for the
software trigger data pattern. This pattern identifies the location
in the data of the investigational features.
[0011] In other embodiments for using and modifying a conventional
disc drive, additional firmware modifications may be made to the
disc drive. In many cases, such firmware changes are ones that are
known in the field of disc analysis and/or drive analysis, but are
not used in conventional disc drive systems and would generally be
considered unnecessary or even undesirable. For example, for
analysis purposes one may want to look at errors that are
generated, automatic gain control values, laser power values, laser
monitor values, and many other parameters relating to the reading
of a disc by a drive. In typical conventional disc drives, however,
a user, such as a consumer, would typically want to use a disc that
plays music or provides data, without setting parameters.
Consequently, conventional systems generally have no need or desire
for monitoring or controlling such other parameters. According to
embodiments of the present invention, firmware changes that are
useful in a disc drive system for detecting investigational
features may be made. For example, in a disc in which a fluid is
provided into a channel to be moved along the channel in response
to rotation, and detected by the laser/detector in a drive, it may
be desirable to be able to control the rotation rate of the disc
when it begins, and also to control the laser power, to avoid
unwanted movement or heating.
[0012] Another use of such firmware changes can be to monitor a
parameter that indicates some useful information about an
investigational feature. For example, automatic gain control can be
provided so that the detector output signal is amplified by a
variable amount. The amount of gain is inversely related to the
amount of light falling on the detector. In a conventional disc,
the device is only reading binary data (0 or 1), but an
investigational feature may require data to be read over a
continuum of values. The level of gain may serve as an indicator of
the investigational feature--the larger the gain the smaller the,
and vice versa. The automatic gain control value can thus be used
to image, detect, or assess the investigational feature.
[0013] While several firmware changes have been mentioned here, the
embodiments below indicate a number of other features that are
useful modifications to a conventional drive. By making these
changes in firmware, the drive capabilities can be modified in some
respects and yet use conventional hardware is modified.
[0014] According to yet another embodiment of the invention,
multiple optical paths are provided, such that various functions of
an optical disc system can be isolated and optimized. For example,
an optical disc system performs a number of functions, including
tracking, focusing, and synchronizing. When each of these functions
manipulates a single signal (e.g., a quad-sum signal), these
functions are said to be linked. The linking of individual
functions can be problematic because the optimal system settings
for performing each of these functions may be different. For
example, in a pits and lands type of optical disc, the optimal pit
depth for retrieving tracking information is 1/8 the wavelength of
the light beam used by the system. In contrast, the optimal pit
depth for retrieving synchronization information is 1/4 the light
beam wavelength. Because only one signal is being used for both
tracking and synchronization, this difference requires that a pit
depth be chosen that optimizes neither the tracking nor the
synchronization functions.
[0015] When multiple paths are used to create distinct signals, the
tracking signal can be isolated from the synchronization signal and
each set of pits can be formed to meet the optimal requirements for
each function. Thus, for example, the pits used for tracking can be
formed with a depth of 1/8 the light wavelength that is used to
read the signal, and the pits used for synchronization can be
formed to be 1/4 the light wavelength that is used to read the
signal.
[0016] In an illustrative optical disc system according to the
invention, one signal can be generated to detect the standard
optical disc operational information, such as tracking, focus, and
synchronization, while another signal can be generated to detect
investigational features or structures disposed on the same or
different surface of the disc assembly. Thus, the system can
separately detect operational data and investigational features
located on one or more surfaces of an optical disc assembly.
[0017] One method of producing multiple optical paths for detecting
operational structures and investigational features is by using a
"three-beam" optical design. In a conventional three-beam design,
for example, a quad-sum detector is used for focus and
synchronization functions. The tracking functions, which can be
performed by two additional signal detectors, known commonly as
"outriggers," are fixed on either side of the quad-sum detector.
Thus, two distinct photometric arrays are provided for detecting
signals from the optical disc assembly. As used herein, a
photodiode array is a set of one or more photo-detector
elements.
[0018] One method of generating multiple coherent or non-coherent
light beams (e.g., three beams for the three-beam system) is by
passing the light through a diffraction grating, which can be a
screen with slits spaced only a few light wavelengths apart. A
one-beam pickup accomplishes all of these tasks with one beam.
[0019] In a system according to the invention, which uses a
multiple-beam pick-up, one beam may also be used to provide all the
tasks of a typical optical system and the additional beams may be
used to detect investigational features or structures on the
optical disc assembly concurrently or nonconcurrently.
[0020] These and other advantages will become apparent from the
following detailed description taken in conjunction with the
accompanying drawing figures and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a perspective view and block diagram of a disc and
disc reading system.
[0022] FIG. 2 is a side cross-sectional view of a disc.
[0023] FIG. 3 is a perspective view of a surface of a CD-R disc
with wobble grooves.
[0024] FIG. 4 is an exemplary optical disc detector and associated
electronics that use three beams for tracking, focusing, and
reading.
[0025] FIG. 5 shows the position of beams from a typical three-beam
pickup relative to a track on an optical disc.
[0026] FIG. 6 is a block diagram of a chip set of a generic optical
disc reader, modified to monitor signals for determining the
presence of investigational features or structures on an optical
disc.
[0027] FIG. 7 illustrates a cross sectional side of a suitable disc
assembly, including a light-refractive cover, for use with the
present invention.
[0028] FIG. 8 is a functional block diagram of a conventional CD
digital signal processing circuit.
[0029] FIG. 9 is a functional block diagram of a digital signal
processing circuit programmably configured as an analog to digital
converter in accordance with the principles of the present
invention.
[0030] FIG. 10 is a block diagram of a known light projection and
detection system.
[0031] FIG. 11 is a prior art view showing a three-beam system
projecting onto three tracks of the disc.
[0032] FIG. 12 is a top view of three beams on three tracks, one of
which has an investigational feature.
[0033] FIG. 13 is a block diagram of an overall drive system
according to an embodiment of the present invention.
[0034] FIG. 14 is a part pictorial part block diagram showing a
disc and a reading system.
[0035] FIG. 15 is a plan view of a disc showing assay regions and a
hardware trigger.
[0036] FIG. 16 is a block diagram of a board with functionality
including a trigger, an amplifier, and detection circuitry.
DETAILED DESCRIPTION
[0037] FIG. 1 shows an optical disc reader system 10. This system
may be a conventional reader for CD, CD-R, DVD, or other known
comparable format, a modified version thereof, or a distinct
dedicated device. The basic components of an optical reading system
are a light system for providing light, motors for rotating the
disc and moving the light system, and a detection system for
detecting light and processing signals.
[0038] A light source 12 provides light to optical components 20 to
produce an incident light beam 14, and a return beam 16. In the
case of a reflective disc or portion of a disc, return beam 16 is
reflected from a reflective surface. Return beam 16 is provided
back to optical components 20, and then to a bottom detector 22.
Optical components 20 can include a lens, a beam splitter, and a
quarter wave plate that changes the polarization of the light beam
so that the beam splitter directs a reflected beam through the lens
to focus the reflected beam onto the detector. An astigmatic
element, such as a cylindrical lens, may be provided between the
beam splitter and detector to introduce astigmatism in the
reflected light beam.
[0039] Data from detector 22 is provided to a computer 25 with a
processor 24 and an analyzer 26 to provide an image to a monitor
28. The computer can represent a desktop computer, programmable
logic, or some other processing device, and also can include a
connection (such as over the Internet) to other processing and/or
storage devices. A drive motor 30 and a controller 32 are provided
for controlling the rotation of disc 40. Methods and systems for
reading such a disc are also shown in the incorporated U.S. Pat.
No. 5,892,577. A hardware trigger sensor 42 may be used. Triggering
sensor 42 provides a signal to processor 24 that allows for the
collection of data by processor 24 only when incident beam 14 is on
a target zone. In this case, data is not collected when the trigger
is not detected. The trigger is preferably aligned radially with
target zones. Trigger sensor 42 may be located on the bottom side
of the disk 40.
[0040] The system may also include a top detector 46 for detecting
transmitted light 44. This light could pass through a
semi-reflective disc, or through a portion where portions of the
disc have been removed.
[0041] The disc drive assembly is thus employed to rotate disc 40,
read and process any encoded operational information stored on the
disc, analyze the liquid, chemical, biological, or biochemical
investigational features in an assay region of the disc, to write
information to the disc either before or after the material in the
assay zone is analyzed by the read beam of the drive. Other than
the trigger sensor and the transmissive detector, the remaining
components are parts of generally known optical disc readers, and
the incorporated '577 patent shows the use of a separate top
detector and bottom detector.
[0042] Referring to FIG. 2, disc 190 has layers from light-proximal
to light-distal, including transmissive substrate 192 (such as 1.2
mm polycarbonate), reflective layer 194 (such as a gold or aluminum
layer), and a protective cap layer 196. Transparent substrate 192
makes up most of the thickness of a typical CD-type disc, as
measured along the optical axis, and provides both optical and
structural features necessary for disc operation.
[0043] Substrate layer 192 is typically impressed with a spiral
track that starts at the innermost readable portion of the disc and
then spirals out to the outermost readable portion of the disc. In
a non-recordable typical CD disc, this track is made up of a series
of embossed pits, each typically having a depth of approximately
one-quarter the wavelength of the light that is used to read the
disc. The pits have varying lengths. The length and spacing of the
pits encode operational data.
[0044] The spiral groove of a recordable disc, such as CD-R has a
wobble groove rather than pits. FIG. 3 shows two portions of such a
wobble groove, i.e., an embossed portion 200 and a groove portion
198.
[0045] Referring to FIG. 4, an exemplary detector 180 and its
associated electronics are described in more detail. Detector 180
typically includes a central detector 182, and can be bordered by
additional detector elements 184 and 186. Central detector 182 may
be split into multiple detector elements, e.g., four, represented
as a, b, c, and d. Detector elements a, b, c, and d (sometimes
collectively referred to as a "quad detector") each provide an
electrical signal indicative of the intensity of the reflected
light beam striking that element.
[0046] The sum of the signals from center detector 182 (i.e.,
a+b+c+d) provides a radio frequency (RF) signal 240, also referred
to as a high frequency (HF), quad-sum, or sum signal. As used
herein the notation "a+b" indicates the sum of the signals from
detector elements a and b. The RF signal is typically demodulated
to recover data recorded on the optical disc.
[0047] Various pairs of the signals from detector elements a
through f are also combined to provide feedback signals for
tracking and focus control. For example, a tracking (tracking
error, or TE) signal 242 may be obtained from the difference
between the e and f signals (i.e., e-f). A focus error (FE) signal
244 may be obtained from the difference between the (a+c) and (b+d)
signals.
[0048] The circuitry of FIG. 4 is just one example of circuitry
that provides focus and tracking error signals in an optical disc
player. Numerous methods are known for providing these signals. For
example, a focus error signal may be obtained by the critical angle
method, described in U.S. Pat. No. 5,629,514, or by Foucault and
astigmatism methods, described in The Compact Disc Handbook by
Pohlmann, A-R Editions, Inc. (1992), which are incorporated herein
by reference. Similarly, tracking error signals may be obtained
using a single beam push-pull or a three beam method described in
The Compact Disc Handbook, a differential phase method described in
U.S. Pat. No. 5,130,963, which is incorporated herein by reference,
or a single beam high frequency wobble method.
[0049] Referring to FIG. 5, a CD drive typically uses a three-beam
pickup, in which the light beam is split into three beams, a main
beam and two tracking beams. The main beam is focused onto the
surface of an optical disc so that it is centered on a tracking
structure, whereas the tracking beams fall on the opposite sides of
the tracking structure. Main beam 210 is shown centered on track
214 (as defined by pits 212), and tracking beams 213 falling on
opposite sides of track 214. By design, the three beams are
reflected from the optical disc and directed to detector 180 (FIG.
4) such that main beam 210 falls on the quad detector, and tracking
beams 213 fall on sensor elements e and f Typically, such
processing is performed by analog circuitry in combination with one
or more integrated circuit chips. Often, the circuitry takes the
form of a special chip set or a single ASIC (application-specific
integrated circuit) chip.
[0050] FIG. 6 is generalized block diagram including an
illustrative chip set 300 for a typical optical drive system.
Although the chip sets for CD, CD-R, and DVD drives can be somewhat
different from one another, it will be understood that the system
shown in FIG. 6 is meant to generically represent all types of
optical drives.
[0051] RF signal 240, obtained from summing the signals from
detector elements a, b, c, and d, is normally processed to extract
whatever data is recorded on the optical disc. First, analog RF
signal 240 is conditioned, with normalization and equalization
performed. Next, RF analog signal 240 is converted to a digital
signal comprising a serial stream of digital data referred to as
channel bits. The channel bit stream is then demodulated according
to the modulation standard used for the type of optical disc being
read. For example, it is common for CD-type discs to use
eight-to-fourteen (also denominated "eight-of-fourteen") modulation
(EFM) wherein a data byte, or eight data bits, are encoded in
fourteen channel bits. There are three merging bits between each
group of fourteen channel bits. Thus, when reading a CD-type
optical disc, seventeen channel bits are read from the optical
disc, the merging bits are discarded, and the remaining fourteen
bits are decoded, or demodulated, to obtain the original data byte.
The data bytes themselves are grouped into blocks, which are
further processed to reduce the effects of disc defects, such as
scratches on the disc surface.
[0052] RF signal 240 from detector 180 may be converted to a square
wave signal 312 by a comparator 310, which provides a high output
when RF signal 240 is above a threshold level, and a low output
when RF signal is below the threshold. Digital signal processing
circuit (DSP) 320 then samples square wave signal 312 to determine
the value of each channel bit. DSP 320 further demodulates the
channel bits to extract the data bytes which are then grouped into
blocks and processed to detect and correct errors that may have
occurred. Memory 330 provides temporary storage for the data as it
is being processed by DSP 320 and assembled into blocks.
[0053] Servo block 340 analyzes tracking error (TE) signal 242 (or
a wobble tracking error (WTE) in a DVD or CD-R system) and provides
a tracking control signal 342 to the tracking mechanisms to ensure
the pickup assembly maintains proper tracking. Similarly, a focus
control signal 344 is provided based on focus error signal FE 244.
DSP 320 provides an indication of the data rate of RF signal 240
which is used by servo block 340 to provide a speed control signal
346 to the spindle motor (not shown) of the optical disc drive.
[0054] In an audio CD player, after processing by DSP 320, each
data block is sent to audio reproduction circuitry (not shown).
However, in some data storage applications, each data block may
contain additional error detection codes (EDC) and error correction
codes (ECC). EDC/ECC circuitry 350 typically uses the EDC and ECC
codes to increase the integrity of the data block by detecting and
correcting errors not already corrected by DSP 320. Memory 332,
which may be combined with memory 330, provides temporary storage
for data blocks being processed by EDC/ECC circuitry 350. The data
blocks are transferred from the optical disc player to a host 370
by means of interface circuitry 360. An ATAPI interface is shown,
but it should be understood that other interfaces, such as SCSI,
Firewire, or Universal Serial Bus (USB), and the like could also be
used.
[0055] Controller 380 coordinates the operation of the various
components of chip set 300, for example by coordinating the
transfer of data blocks between DSP 320 and EDC/ECC circuitry 350.
Controller 380 also keeps track of which data block is being read
and may keep track of various parameters indicative of the
operational status of the optical disc reader.
[0056] Program memory 390 has program code for the operation of
controller 380. In many optical disc reader chip sets, program
memory 390 may also contain program instructions for DSP 320 or
EDC/ECC circuitry 350. This is advantageous for manufacturers in
that the operation of the disc drive may be changed by altering the
program code in program memory 390. For example, a newly developed
method of modulating or encoding data on an optical disc may be
accommodated by changing program memory 390.
[0057] While the foregoing description is sufficient for a basic
understanding of the present invention, there are numerous
alternative designs and configurations of an optical pickup and
associated electronics which may be used in the context of the
present invention. Further details and alternative designs are
described in Compact Disc Technology, by Nakajima and Ogawa, IOS
Press, Inc. (1992); The Compact Disc Handbook, Digital Audio and
Compact Disc Technology, by Baert et al. (eds.), Books Britain
(1995); CD-Rom Professional's CD-Recordable Handbook: The Complete
Guide to Practical Desktop CD, Starrett et al. (eds.),
ISBN:0910965188 (1996); which are incorporated herein in their
entirety by this reference.
[0058] To this point, the circuitry of FIG. 6 is known in prior
optical disc drives. Chip set 300 can be modified from its original
configuration by the addition of tap buffers 260, 270, and 280.
These tap buffers provide access to unprocessed analog signals such
as RF signal 240, TE signal 242, and FE signal 244, respectively,
produced by detector 180, thereby permitting external
instrumentation to receive these signals without interfering with
normal drive operation.
[0059] An alternative modification is the addition of tap buffers
to allow the unprocessed a though f signal from detector 180 to be
processed by external instrumentation or additional circuitry. From
these signals, the HF, TE, FE, or any other combination can be
formed. Also, any additional detectors available can provide useful
signals in this same manner (e.g., g and h detectors in current
state-of-the-art drives) certain drive circuit designs and
detector/amplifier devices allow connection of the instrumentation
or additional circuitry directly to the detector without the need
for the tap buffers.
[0060] The U.S. patent applications incorporated in the background
section, including Ser. No. 09/183,842 (hereinafter the '842
application) discloses coupling an oscilloscope to RF signal 240
for detecting dual peak profiles associated with nonoperational
structures or investigational features while acquiring the
information needed to operate the disc drive. These peaks appear as
a result of changes in reflectance as the light beam traverses
investigational features on the optical disc surface. Such unique
electronic profiles may be advantageously used to detect and
discriminate among investigational features. An external analog to
digital converter (ADC) may be connected to RF signal 240, for
example, in order to determine the number of unique electronic
peaks encountered (and thus the number investigational features) on
any portion of the optical disc. The magnitude and/or duration of
the digitized unique electronic profiles may be interpreted by an
associated application program to determine the relative size,
composition, and location of the detected structures.
[0061] The '842 application teaches that micron-sized
investigational features may be disposed upon a surface of an
optical disc in a number of ways. One suitable embodiment for
accomplishing this is depicted in FIG. 7. As shown in FIG. 7, light
beam 50 is incident on the disc assembly from below. Disc 52 has
disc substrate 54 and reflective layer 56, upon which
investigational features 136 are disposed. Wobble groove 58,
impressed in substrate 54 and coated by reflective layer 56, is
indicated. Also shown is a nonintegral cover 60.
[0062] Investigational features 62 may be detected, measured, and
characterized if reflective layer 56 is not fully reflective. The
operational structures of the disc, including tracking features,
may be detected concurrently (or nonconcurrently) with and readily
discriminated from investigational features using a single optical
pickup.
[0063] Investigational feature 63 is shown in a target zone in
which the reflective layer is removed, thereby allowing light to be
transmitted more easily without a reflective or semi-reflective
layer. The disc can have a number of target zones 65, and these are
preferably aligned along radii of the disc.
[0064] The material applied to the disc for investigation and
analysis may include biological particulate suspensions and organic
material such as blood, urine, saliva, amniotic fluid, skin cells,
cerebrospinal fluid, serum, synovial fluid, semen, single-strand
and double-strand DNA, pleural fluid, cells from selected body
organs or tissue, pericardial fluid, feces, perintoneal fluid, and
calculi. In the case of some of these materials, a reporter may be
employed for detection purposes. These reporters include plastic
micro-spheres or beads made of, for example, latex or polystyrene
and colloidal gold particles with coatings of bio-molecules that
have an affinity for a given material such as a biotine molecule in
a strand of DNA. Appropriate coatings include those made from
streptavidin or neutravidin, for example. In this manner, objects
to small to be detected by the read beam of the drive, may still be
detected by association with the reporter.
[0065] To acquire information concerning the investigational
features, a standard suitable detection circuit can be coupled to
the unprocessed RF signal. The type of signal processing performed
by DSP 320, which typically includes demodulation, decoding, and
error checking, is intended to convert EFM-encoded information on
the RF signal to a specific digital format. RF signals processed in
this manner may be less desirable for detecting the dual peaks
associated with investigational features.
[0066] FIG. 8 is a functional block diagram illustrating the signal
processing that occurs within DSP 320 when configured in a
conventional manner. As shown, DSP 320: (1) equalizes and/or
normalizes the RF signal (block 400); (2) converts the normalized
RF signal from the analog to digital (block 420); (3) demodulates
and decodes the resulting EFM signal (block 440); (4) performs an
error checking procedure (e.g., using Cross-Interleaved
Reed-Solomon Code "CIRC" block 460); and (5) provides the resulting
signal to an output interface for communication with host data bus
(block 480). Examples of commonly used DSP chips that perform some
or all of these functions include the SAA 7210, SAA 7220, and the
SAA 7735, available from Philips Electronics Corporation,
Eindhoven, Netherlands.
[0067] In accordance with one embodiment of the present invention,
chip set 300 is reconfigured and/or reprogrammed so that physical
modification of the optical disc drive is not necessary. One way
this may be accomplished is by programming DSP 320 to operate
simply as an A/D converter, and bypassing other functionality, such
as the demodulator and decoder functionalities. In such a
configuration, DSP chip 320 takes the place of an external A/D
converter and effectively shunts the digitized RF signals directly
to host data bus 370.
[0068] Investigational features may be detected by analyzing the
resulting digitized RF signal. Alternatively, investigational
features could be detected by routing an unprocessed RF signal
through the chip set to an output terminal of the disc drive,
connecting the signal to a personal computer, and using hardware
and software within the personal computer to perform the A/D
conversion and analysis.
[0069] DSP 320 can be programmably configured as an A/D converter
without additional demodulation and error correction in multiple
ways. For example, a configuration routine stored in program memory
390 may operate via controller 380 to reconfigure DSP 320.
Alternatively, an application program may be used to selectively
reconfigure DSP 320 through interface circuitry 360 as required.
DSP 320 may also configure itself as an A/D converter when it
receives a certain type of RF signal, or from other information
read from the disc. These methods are merely illustrative, and any
other suitable software or firmware based reconfiguration method or
path may be used if desired.
[0070] FIG. 9 shows a block diagram illustrating some of the ways
in which the processing resources within DSP 320 may be
reconfigured to produce a suitable A/D converter. In one
arrangement, A/D block 420 is disconnected from paths 450 and
connected directly to output interface 480 through path 430. In
this case, digitized RF signals completely bypass blocks 440 and
460 and travel to output interface 480. In another arrangement,
digitized signals from A/D block 420 travel on paths 450, but pass
through blocks 440 and 460 without being processed. In some
embodiments, it may be desirable to turn off blocks 440 and 460 or
place them in a low power operating mode to reduce power
consumption (e.g., in battery operated disc drives). Although the
foregoing illustrates several possible A/D converter arrangements,
any other suitable arrangement of resources within DSP 320 may be
used if desired.
[0071] If the bypassing of unneeded functionality can be
accomplished through programming, no change to existing hardware is
needed, although a modification may be needed to drive
firmware.
[0072] FIG. 10 shows a conventional single objective assembly 100
designed for multiple (e.g., three-beam) light projection and
detection. Light source 110 is placed at a focal point of a
collimator lens 140 that normally has a long focal distance. Lens
140 makes the divergent light rays parallel. A monitor diode (not
shown) may be used to stabilize the laser's output. Light source
110 may be a laser, LED, or laser diode, although the invention may
be implemented on a non-coherent light system as well.
[0073] A conventional optical design used for three-beam pickup
typically uses two secondary beams for tracking. To generate these
beams, light from source 110 passes through diffraction grating
120, which is a screen with slits spaced only a few laser
wavelengths apart. As the beam passes through the grating, the
light diffracts; when the resulting collection is again focused, it
will appear as a single, bright, centered beam with a series of
successively less intense beams on either side. It is this
diffraction pattern that actually strikes the disc.
[0074] A conventional three-beam pickup uses the center beam for
reading data and focusing and two secondary beams for tracking
only. In this design, the beams are spatially-linked because they
are the result of a single diffracted laser beam. A one-beam pickup
accomplishes all of these tasks with one beam.
[0075] Polarization beam splitter 130 (PBS) passes transmitted
light to a disc surface and then directs the reflected light to a
photodiode sensor 180. PBS 130 normally includes two prisms with a
common 45.degree. face acting as a polarizing prism. Collimator 140
preferably follows PBS 130. The light then passes through a
quarter-wavelength plate 150, which is an anisotropic material that
rotates the plane of polarization of the light beams. Light that
has passed through quarter-wavelength plate 150 and that has been
reflected from disc 190 back again through quarter-wavelength plate
150 will be polarized in a plane at right angles to that of the
incident light. Because PBS 130 passes light in one plane, (e.g.,
horizontally polarized) but reflects light in the other plane
(e.g., vertically polarized), PBS 130 deflects the reflected beam
toward sensor 180 to read the digital data.
[0076] The final piece of optics in the optical path to disc 190 is
objective lens 160, which is used to focus the beams on the disc
data surface, taking into account the refractive index of the
polycarbonate substrate of disc 190. Objective lens 160 focuses the
light into a convergent cone of light. The convergence is a
function of the numerical aperture of the lens.
[0077] The data encoded on disc 190 now determines the fate of the
laser light. In a regular CD, when the spot strikes a land, the
smooth interval between two pits, light is almost totally
reflected. When it strikes a pit with a depth of about a quarter
wavelength of the light, diffraction and cancellation due to
interference cause less light to be reflected. All three intensity
modulated light beams return through the objective lens 160,
quarter-wavelength plate 150, collimator 140, and PBS 130. Finally,
these beams pass through singlet lens 170 and a cylindrical lens
175 en route to photodioide 180.
[0078] FIG. 11 shows three light spots which are produced by a
typical three-beam optical design incident on an optical disc
assembly having pits 90. Laser beam spots 92, 94, and 96 are
illustrated as dashed lines on the surface of the optical disc.
These beams can be focused on the same surface of the disc as pits
90, or on any other outer surface or inner surface of the disc.
These beams can also be focused on different layers of the disc, a
"layer" referring to any portion of the disc that has a finite
thickness.
[0079] In a conventional three-beam optical disc system, detectors
a, b, c, and d, as shown in FIG. 4, are configured to detect light
reflected from a beam spot 92, as shown in FIG. 11. Also, each of
detectors e and f are configured to detect the reflected light from
one of beam spots 94 and 96. As mentioned above, this configuration
has been implemented such that focus and synchronization
information are provided by light reflected at beam spot 92 and the
tracking information is provided by light reflected at beam spots
94 and 96.
[0080] FIG. 12 shows an investigational feature 98 disposed on a
surface of an exemplary optical disc assembly. In this arrangement,
beam spot 92 can be used to detect operational structures (e.g.,
pits) for tracking, focus and synchronization and beam spot 96 can
be used simultaneously to primarily one or more investigational
features 98. Alternatively, beam spot 94 may be used to detect
investigational feature 98, depending on the size and location of
investigational feature 98.
[0081] Also, if investigational feature 98 is sufficiently large,
beam spots 94 and 96 can be used in combination (though not
necessarily simultaneously) for detecting a single investigational
feature 98. It will be appreciated that a combination of patterns
from each of the beam spots can be used to detect the size and
position of investigational feature 98. Also, patterns from
detectors a, b, c, and d can be combined with patterns from one or
both of detectors e and f to determine the size and position of the
investigational features.
[0082] Thus, operational structures and investigational features
can each be detected by different optical paths using a single
objective assembly. It will be appreciated that the invention
disclosed herein relates to the detection of operational and
investigational features and is not limited to an optical disc
assembly having a pits and lands format. Rather, the invention can
be used with any other format.
[0083] FIG. 13 shows a block diagram of a computer and a disc
drive, such as a CD-R system. The known CD-R system can include a
laser and detection circuitry as shown in FIGS. 4 and 6 for
detecting reflected light. According to an embodiment of the
present invention, additional CD-R drive functionality, including a
detector for transmissive light, and a trigger detector, and
processing circuitry, preferably on a single printed circuit board
(PCB) 504, is added to the CD-R drive housing. This functionality
thus detects transmitted light, trigger marks, and amplifies an
analog data signal based on the detected transmitted light. These
additions are preferably made so that no change is needed to
existing CD-R electronics, and thus a conventional optical disc
drive may be modified prior to initial shipment or retrofitted with
the additional functionality without the need to alter the CD-R
hardware. While using existing functionality has advantages, any
changes made to a disc reader could be done by making changes to or
modifying an existing reader.
[0084] A trigger signal 506, indicating whether a trigger is
identified, and an analog data signal 508 are both provided to an
analog-to-digital converter (ADC) 510. ADC 510 collects data when
the trigger signal indicates detection of a trigger mark, and does
not collect data when a trigger mark is not detected.
Alternatively, the trigger signal could be provided in the
operational data, such that encoded information on the disc
indicates the location of the investigational features.
Alternatively, the entire disc is scanned to read all the data on
the disc, but only data following a predefined set of data. In this
way, all the data on the disc can initially be read into memory,
but then the data other than that following the software trigger
can be discarded.
[0085] Optionally, a second trigger mark can be provided as well.
This second mark can be useful to distinguish from among multiple
target zones and better enables the user to look at a particular
zone rather than all the zones. One trigger mark and one trigger
mark detector must be located at a different radius than all of the
others.
[0086] ADC 510 also receives analog drive signals via a buffer PCB
512 which receives its input signals from CD-R drive 502. A CPU
motherboard 516 communicates with the CDR drive 502 over a small
computer systems interface (SCSI) 518 and receives data through an
expansion bus from ADC 510. CPU motherboard 516 has an Ethernet
connection that allows this data to be offloaded for further
processing.
[0087] A power supply 524 receives a power input 526 and provides
the power to the motherboard 516 as well as to the other components
in the CDR drive housing 500 and in the PC.
[0088] The data can be processed as it is collected in a real-time
manner, or may be stored and post processed by other computers,
potentially reducing the complexity of the system.
[0089] The trigger, amplifier, detector (TAD) PCB 504 is preferably
constructed in such a manner that it can be provided into a
conventional optical drive of the type that can be used in a drive
bay in a computer. One suitable drive used particularly for
development purposes is the Plextor model 8220 CD-R drive. While a
CD or DVD can be used, a CD-R drive has several useful aspects.
Because the CD-R drive allows reading and writing functions, the
laser can operate over a higher range of power levels. This
functionality of using higher power can be useful for certain types
of investigational features. Another useful aspect of a CD-R is
that it has the ability to write onto a disc and therefore can be
used to write results back onto a disc. This allows results to be
saved back onto the disc for later use and to remain with the
disc.
[0090] FIG. 14 is a block diagram that illustrates in more detail
the inter-relationship between TAD PCB 504 and the disc drive
mechanisms. As it is shown here, optical components 530 are mounted
on a sled 532 that is driven by a sled motor 534, and the disc is
driven by a disc motor 542. These two motors are driven by drivers
544 that receive signals from CPU 516 and may be conventional and
known. Data from the optical components 530, triggering detector
signal 506, and signals 508 from a transmissive detector or
detector array 548 are all provided to PCB 504. The detector for
processing the signal from the transmitted or reflected beam of
light may be a single detector element or an array of multiple
elements arranged radially or circumferentially, and may be placed
on the opposite side of the disc from the laser, and may be mounted
directly on the PCB or separately.
[0091] Referring also to FIG. 15, which is a plan view of a disc
showing sample areas and triggering mark, the hardware trigger is
preferably disposed at an outer periphery of the disc, and
preferably is in a radial line with sample areas 550. The trigger
indicates that the light beam is in a radial line with sample areas
550 and allows the ADC to process data. This trigger helps to
reduce the amount of data that is collected.
[0092] Referring to FIG. 13, the trigger functionality,
amplification circuitry, and transmissive light detection are
preferably performed on a single PCB and preferably have a size,
shape, and configuration that allow it to be incorporated into
existing commercial disc drives.
[0093] The ADC may be on a sampling card that allows for very high
speed conversion. One usable card is the Ultrad AD 1280 DX, which
has two 12-bit A/D converters sampling up to forty million samples
per second.
[0094] There are advantages to making changes to the disc drive
that provide the least amount of disruption to conventional drives.
For this reason, it can be desirable to use a disc that is
transmissive. In other words, the disc is reflective enough for the
operational data to be seen by the active electronics and normal
drive functioning to occur. Yet, the light passes through the disc
to a detector on the other side of the disc. In this manner, the
investigational features can be detected without it being necessary
to alter the detection circuitry for reflected light. The reflected
light may still be used to read encoded data.
[0095] One way to cause fewer changes is to provide a board that
will fit within the space of a conventional housing and which is
over the disc on the opposite side of where the laser is
situated.
[0096] Referring to FIG. 16, PCB 504 can include a transmissive
detector 548 located over the viewing regions. This detector can be
a single detector, an array arranged with different segments
oriented radially, or an array with multiple segments oriented
circumferentially with multiple detectors arranged along different
radii. The detector receives signals and provides them to a
preamplifier 560, automatic gain control 562, switch 564, and
amplifier 566 to produce a signal on the order of 3 volts.
[0097] Triggering light source and detector 570 can be provided on
PCB 504. This hardware would include a light source and a detector
positioned to detect trigger marks, preferably at the periphery of
the disc 572. The trigger signal is provided to the ADC such that
the ADC only collects and stores data when the triggering signal
indicates that the system has detected a trigger, thereby saving on
the processing that is required and the data that is stored. A
second trigger light source and detector 574 can be provided in
order to help distinguish from among a plurality of trigger marks.
In this case, both trigger signals are provided to a trigger
control circuit. The trigger control circuit passes trigger signals
to collect and retain data from the desired sample areas on to the
ADC.
[0098] As an alternative to this hardware triggering, a software
trigger could be used.
[0099] Analog switch 564 can be used when the data detector is an
array with multiple elements. There can be multiple detector
elements that perform some of the types of refracted light
combinations. For example, sums and differences can be used. If
desirable, the switch can also be coupled to the detection elements
that are under the disc for detecting reflected light. This could
allow the system to obtain a differential between the top and
bottom detection.
[0100] Additional processing and counting functionality can be
provided on the PCB in order to move the processing from the ADC
510 and external computer or effectively to replace the ADC and
computer to provide that more processing occur on the PCB. In the
case of the test for CD4/CD8, for example, one methodology that is
used is to count white blood cells in a target region. As the laser
light is scanned over the assay region, the detector will detect no
light at the edge of a blood cell, and will detect full light when
centered on a blood cell. As the beam is scanned, it therefore
creates a series of high and low signals indicating where a cell is
detected. Processing functionality can be added to the card to
include threshold crossing circuitry and a counter. Such processing
is less complex than that that may be used for other tests. Each of
these types of circuits is generally known. Depending on the type
of test that is used (the CD4/CD8 being one example), the
processing system may need to count hundreds or up to tens of
thousands of features in the assay region. In addition, a
microprocessor could also be added to the card.
[0101] By providing additional processing and/or counting
functionality onto the card, the results from scanning the sample
can be provided directly from the card for direct use, such as to a
USB port or through an Ethernet port. By using Ethernet, data can
be provided from a web server such that users can access data with
a web browser.
[0102] The PCB can also include a temperature sensor and other
sensors (not shown) that may be useful for testing. In the case of
temperature, a test, may use a level of darkness in a material to
indicate the relative presence of some material. For example, a
glucose test may rely on the darkness of a fluid, and thus
colorimetry is used. For tests for which temperature is a factor,
the temperature sensor can be used and can be a factor used in the
processing of the data.
[0103] Another detector that can be provided is a simple barcode
reader that can be used if barcodes are provided on the disc for
identification purposes.
[0104] The automatic gain control (AGC) 562, and also automatic
level control (ALC), makes sure that the full dynamic range is
used, and thus the signals may range, for example, from 0 to 3
volts. ALC is used to define a center of the signal, such as 1.5
volts if the range is 0 to 3 volts. The result of the
amplification, ACG, and ALC is that the output can be processed
through a threshold circuit and provide consistent results.
[0105] So far, this application has described one method in which
the processing of reflective light intensity is utilized to provide
for the detection of investigational features. This application has
also described a system and method by which hardware can be added
to a conventional optical disc drive in order to use light that is
transmitted through the disc. Another approach for modifying
conventional disc drive, preferably without the need to modify the
electronics or hardware, is to use firmware modifications to
monitor known signals within the disc drive. The value of the AGC
can be useful as an measuring tool. The AGC functionality tries to
ensure that the analog output signal has a consistent range. If the
disc drive is used to read binary data, only a high value and a low
value are needed. In the case of investigational features, however,
values may be desirable over a continuum of ranges. The AGC is high
where the signal level is low, and vice versa. The AGC can thus be
used as a signal that is representative of the light that is
received by the detector, and therefore can be used for measurement
and detecting changes in an investigational feature.
[0106] A conventional optical disc reader is generally provided to
a user to allow the user to play a disc with little ability to
control the parameters of the reading, rotating, and data
processing; for the most part, users of commercial CD and DVD
players would not need such abilities (and likely would not want to
have to set parameters).
[0107] The changes set out below, for the most part, are ones that
do not require hardware change, and for the most part are typical
of modifications that may be made in disc and drive analysis
systems in which various parameters of discs and drives are
measured and refined. In the case of a regular CD or DVD commercial
product, however, these changes would generally not be made and
would be unnecessary.
[0108] These changes can be made in firmware, and generally can be
made by post-purchase software modification. In other words, the
programming could be provided to a user on a disc or by download,
and thus no hardware changes are required. These programming
changes could be read from a disc, e.g., at startup, and used to
modify the ability to control the operation of the drive.
[0109] The changes can include one, all, or some combination of the
following capabilities:
[0110] 1. Wobble groove playback and random access on a wobble
groove: rather than needing to start from the beginning of a disc;
this change allows the drive to go to an LBA (or an address by some
other mode) and play forward from there.
[0111] 2. Poll the laser monitor value: allows reading of the value
of the laser power detected by the laser power monitor detector in
the optical pickup unit.
[0112] 3. Poll and set the laser power read/play value: monitor and
set the power command value to the laser to allow a range of
values.
[0113] 4. Poll the automatic gain control (AGC): ability to get the
value of the AGC. The gain is controlled to make sure that the
detected signals have a consistent amplitude. The amount of gain
therefore is an inverse indicator of the signal intensity.
Consequently, the signal can be used for detection and
measurement.
[0114] 5. Poll the tracking automatic gain control value.
[0115] 6. Monitor the C1 and/or P1 decoder activity at a port: this
change, and the one in (7) below, relate to the ability to monitor
types of errors to see the error counts; this is useful because the
errors could be useful information for detecting where an
investigational feature is. A conventional drive detects gaps in
the encoded data as an error.
[0116] 7. Monitor the C2 and/or PO decoder activity at a port: see
(6) above.
[0117] 8. Initialize and track operational features on a disc
independent of encoded logic: This refers to the ability to control
the laser position and control the speed of the disc independent of
the data. This functionality allows a user to send a command to
keep the drive motor spinning without its operational functions of
focus, tracking, and synchronization.
[0118] 9. Initialize the drive with a specific speed and laser read
power: a drive typically has a start-up speed and laser power that
is not changed by a user; this change allows these values to be set
and changed by the user. Because a liquid is being provided to the
disc, it may be desirable not to spin the disc as soon as it is
provided into the disc drive. In a typical disc drive system,
however, the disc immediately starts to spin to get a focal point,
get synchronization information, and find a table of contents;
typically if these are not found, the disc drive will open up and
shut down. As indicated above, because liquid is provided, it may
be desirable to not spin the disc as soon as it is provided into
the disc drive but to wait for further instructions. This change
also relates to the change set out in No. 15 below.
[0119] 10. Stream the main and sub-channel data in all areas of the
disc including lead-in and lead-out: allows more portions of the
disc to have data.
[0120] 11. Push raw-EFM (eight-fourteen modulation) value to a port
or secondary port: allows the user to see 14-bit data before it is
translated to 8-bit values. This functionality allows the user to
more clearly know exactly what is on the disc. Like No. 10 above,
this change allows additional areas on the disc to be used.
[0121] 12. Push buffered, DC coupled signals, such as TE, FE, and
HF, to an external port; relates to the ability to provide these
values to a port to be used, where generally they are used for
internal purposes (see FIGS. 4 and 6).
[0122] 13. Decode and poll values collected from the power
calibration area (PCA) and program memory area (PMA) at
initialization. Allows additional information to be collected.
[0123] 14. Pause playback of a disc and open the tracking servo to
monitor the open loop tracking signal: allows the user to monitor
the eccentricity of the disc. A disc generally had some
eccentricity and therefore the tracking signal will have a periodic
form as the disc is rotated. The eccentricity of the disc arises
from nonperfect processing of the disc. The tracking signal is thus
a reflection of the eccentricity which produces a periodic signal
that is a reflection of the eccentricity. If there is a change in
reflectivity in one area, such as due to the presence of an
investigational feature, the tracking signal will reflect this
change in reflectivity.
[0124] 15. Set Ghost initialization logic: As indicated in No. 9
above, when a disc is put into a disc drive, it typically starts up
and one of the initial functions is to find a table of contents. If
the disc is not spun initially, there will not be a table of
contents found. Accordingly, this change allows the user to provide
to the disc drive controller a table of contents to effectively
trick the disc drive into thinking that it has read the table of
contents from the disc.
[0125] 16. Interactively turn off tracking function.
[0126] 17. Control and monitor the focusing offset with or without
the tracking function. The focus offset changes the size of the
laser spot, and thereby changes the amount of energy. It may be
desirable to provide heating to the disc or a region of the disc,
and therefore the ability to control the focus offset can allow the
user to control the heating.
[0127] 18. Switch layers on a DVD.
[0128] 19. Monitor value changes at the switching port:
[0129] 20. Read a CD or CD-RW with a DVD laser: the DVD laser is at
a lower wavelength, which can be useful for imaging and for
fluorescent detection. Devices that have the ability to read CD and
DVD are generally provided with two lasers, one for each mode.
[0130] 21. Track a wobble groove (1.2 mm) at any frequency with a
DVD laser.
[0131] 22. Monitor the value of a buffered DPD signal: The
differential phase detection (DPD) signal is a DVD signal used for
tracking, and thus this corresponds to previously discussed ability
to monitor the tracking signal.
[0132] These changes can primarily be made in a firmware, which is
generally more preferable and allows retrofitting a commercial
product for use in detecting investigational features, but could
alternatively be done in hardware.
[0133] Having described certain embodiments, it should become
apparent that modifications can be made without departing from the
scope of the claims as set out below. For example, the terms over
and under are used for reference purposes and not absolute
positioning. The disc could be read with reflected light from the
top or the drive could be on its side.
* * * * *