(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
(19) World Intellectual Property Organization
(43) International Publication Date (10) International Publication Number
13 June 2002 (13.06.2002) pCT WO 02/47074 A2
(51) International Patent Classification^: GllB 7/0065, (81) Designated States (national): AE, AG, AL, AM, AT, AU,
(21) International Application Number: PCT/ILO 1/0 1124
(22) International Filing Date: 5 December 2001 (05,12.2001)
(25) Filing Language: English
(26) Publication Language: English
7 December 2000 (07.12.2000) US
(30) Priority Data:
(71) Applicant (for all designated States except US): CON-
SELLATION TRID INC [US/US]; 805 Third Avenue
14th floor. New York, NY 10022 (US).
(72) Inventors; and
(75) Inventors/Applicants (for US only): LEVICH, Eugene
[IL/IL]; 40/54 Yehuda Hanassi, 69393 Tel Aviv (IL).
MAGNITSKII, Sergei [RU/RU]; 9-76 Garibaldi street,
117192 Moscow (RU). JAKOBOVICH, Sergei [RU/RU];
11/22, Art. 1, 1st Neopalimovsky per., 119121 Moscow
AZ, BA, BB, BG, BR, BY, BZ, CA, CH, CN, CO, CR, CU,
CZ, DE, DK, DM, DZ, EC, EE, ES, H, GB, GD, GE, GH,
GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC,
LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW,
MX, MZ, NO, NZ, OM, PH, PL, PT, RO, RU, SD, SE, SG,
SI, SK, SL, TJ, TM, TR, TT, TZ, UA, UG, US, UZ, VN,
YU, ZA, ZM, ZW.
(84) Designated States (regional): ARIPO patent (GH, GM,
KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZM, ZW),
Eurasian patent (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM),
European patent (AT, BE, CH, CY, DE, DK, ES, FI, FR,
GB, GR, IE, IT, LU, MC, NL, PT, SE, TR), OAPI patent
(BF, BJ, CF, CG, CI, CM, GA, GN, GQ, GW, ML, MR,
NE, SN, TD, TG).
— without international search report and to be republished
upon receipt of that report
For two-letter codes and other abbreviations, refer to the "Guid-
ance Notes on Codes and Abbreviations" appearing at the begin-
ning of each regular issue of the PCT Gazette,
r<l (54) Title: APPARATUS FOR RECORDING ON AND/OR RETRIEVAL FROM FLUORESCENT OPTICAL CLEAR CARD
(57) Abstract: There Is disclosed a random-access light-emitting dot matrix used for data writing process. The number and dispo-
sition of dots in the matrix is the same as the number and disposition of pits on one page of one information layer of the fluorescent
multi-layer optical card. Written information can be retrieved page by page.
APPARATUS FOR RECORDING ON AND/OR RETRIEVAL
FROM FLUORESCENT OPTICAL CLEAR CARD
THE FIELD OF THE INVENTION
This invention relates to optical memory systems for recording
and/or retrieval information and more particularly, to fluorescent multi-layer
10 optical card.
THE BACKGROUND OF THE INVENTION
The existing optical memory systems utilize two-dimensional data
carriers with one or two information layers. Most of previous technical
15 solutions in optical data recording propose registration the changes in
reflected laser radiation intensity in local regions (pits) of the information layer.
These changes could be a consequence of interference effects on the relief of
optical discs of CD or DVD ROM-type, burning of holes in the metal film, dye
bleaching, local melting of polycarbonate in widely-used CD-R systems,
20 change of reflection coefficient in phase-change systems, etc.
Three-dimensional, i.e. multi-layer, optical storage systems provide
comparatively higher storage and recording capacity. However this imposes
specific limitations on and requirements to the design and features of optical
information carrier, ways of data recording and reading, especially in the
25 depth of the carrier.
In reflection mode every information layer of the multi-layer optica!
information carrier should possess partly reflective coating. It reduces
intensity of both reading and reflected information beam because of passing
through media to the given information layer and back to the receiver.
30 Besides, due to their coherent nature, both beams are subject to
hardly estimated diffraction and interference distortions on fragments ( pits
and grooves) of the information layers on their way.
Multi-layer fluorescent optical information carriers with fluorescent
reading are preferable as they are free of partly reflective coatings.
Diffraction and interference distortion in this case will be much less due
5 to non-coherent nature of fluorescent radiation, its longer wavelength in
comparison with the reading laser wavelength, and transparency and
homogeneity (similar refractive indices of different layers) of the optical media
towards the incident laser and the fluorescent radiations. Thus, multi-layer
fluorescent carriers have some advantages over reflective ones.
10 The system based on an incoherent signal (fluorescence,
luminescence) has twice as high spatial resolution as coherent methods
(reflection, absorption or refraction) ( see Wilson T., Shepard C. "Theory and
Practice of Scanning Optical Microscopy", Academic Press, London, 1984).
Using the incoherent signal the multi-layer optical memory one can get as
15 high as eight times increasing of information capacity.
SUMMARY OF THE INVENTION
Thus, there is provided in the present invention random-access
light-emitting dot matrix used in the writing process. There are several ways to
20 realize such light source: matrix of light emitting diodes (LED) (solid-state or
organic) or matrix of vertical cavity surface emitting lasers (VCSEL) integrated
with computer-controlled microelectronic circuitry, as well controllable
transparency or controllable matrix of micro mirrors spatially modulating the
external laser beam]. The number and disposition of dots in the matrix is the
25 same as the number and disposition of pits on one page of the FMC
information layer. The actuator-driven micro lens forms the image of the dot
matrix on the selected page. During writing only those dots are switched on
that correspond to "1"-bits. To focus on another page in the same column, the
micro lens is moved perpendicular to the FMC plane. To focus on another
30 page in the same layer, the Clear Card itself is moved.
Written information can be retrieved page by page from the
fluorescent signal. To initiate fluorescence one column of pages is illuminated
by emission of the light source (laser or LED) of the appropriate wavelength.
The magnified image of the requisite page is generated on the
5 receiving surface of the CCD camera using a micro lens and a
semitransparent mirror. To attain maximum contrast of the CCD camera
output signal, the illuminating emission must be filtered. For this purpose a
dichroic mirror with the appropriate spectral pass band may be used. Another
possibility to filter illuminating emission is to use a polarizer or Notch filter
10 based on liquid crystal instead of the dichroic mirror.
BRIEF DESCRIPTION OF THE DRAWINGS
These constructional features and advantages of the invention will
become more clearly understood in the light of the ensuing description of
15 preferred embodiments thereof, given by way of example only, with reference
to the accompanying drawings, wherein -
Fig. 1 is a schematic representation of one of the preferred
embodiments of the fluorescent multi-layer optical clear memory card;
Fig. 2 is one of possible embodiments of parallel reading-writing mode
20 device using the fluorescent multi-layer information carrier; and
Fig.3 is another embodiment of data reader-writer using the fluorescent
multi-layer information carrier.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Below a description of the present invention is given with reference to
Fig. 1 schematically presents one of the variants of Fluorescent Multi-
layer Card (FMLC) 10 comprising the following basic components: rectangular
30 parallelepiped-like thick substrate 1 1 , fluorescent multi-layer information
carrier (FMC) 1 2 and protection layer 20 to protect the optical recording
system from mechanical damage and aggressive media.
Substrate 1 1 is a nontransparent plastic plate designated for
mechanical fixing of FMC 12 and mounting of FMLC 10 in the reader-writer.
For the case when the unit forming reading radiation and the unit recording
5 fluorescent information signal in the reader are disposed on different sides of
FMLC, insert 13 made of optically transparent material is provided at the
location of FMC 12. Holes 14 serve for precise positioning of FMLC in the
reader-writer. FMC 14 is made as a multi-layer structure wherein fluorescent
information carrier layers 18, 0.1-1 \xm thick, are separated by reader-, writer-
10 and fluorescence-transparent radiation polymer layers 10-70 nm thick. To
prevent spurious reflection on the boundary of layers 18 and 19, their
refraction indices are preferably chosen equal within the wavelength range of
the above-mentioned types of radiation.
For the WORM (write once - read many) mode operation, the
15 information carrier waves are photosensitive and contain uniformly distributed
at the molecular level photosensitive and other components, among them
non-fiuorescing dye precursors, photochemically generating colored
fluorescing dyes or compositions loosing their fluorescing properties under the
action of writing radiation.
20 In accordance with the present invention, information is read page-by-
page using, for instance, a CCD camera, at the velocity of the order of 0.1-
0.001 frame/s. This enables utilization of luminophores with long-life excitation
state including organic lumonophores with long-life phosphorescence,
excimers and exciplexes with long-life luminescence as well as inorganic
The recorded data are stored as a multitude of pages 1 5 comprising a
host of individual fluorescing marks 17 (analogs of reflecting pits in known
CD- or DVD-ROM), disposed along rectilinear tracks 16.
In addition to information layers wherein WORM information is
30 recorded, FMC can also include ROM address layers with service information
recorded, such information is particularly designated for positioning of the
reading head relative to FMC,
Several pages located at different information layers one above
another form a "pile of pages" or an information "frame". From said frame data
can be retrieved without mechanical displacement of the reading head in the
5 FMC plane by means of refocusing of the lens from one page located
in one layer to another one located in another layer. The FMC address layer
serves for centering of the frame and is either the first or the last layer within
In the present invention, a random-access light-emitting dot matrix is
10 used for data reading. (There are several ways to implement such source of
light: matrix of light-emitting diodes (LED) - solid-state or organic - or matrix
of vertical cavity surface emitting lasers (VCSEL) integrated with computer-
controlled microelectronic circuitry, as well as a controllable transparency or
controllable matrix of micro mirrors spatially modulating the external laser
15 beam.) The number and disposition of dots in the matrix is the same as the
number and disposition of pits on one FMC page. The actuator-driven lens
forms the dot matrix image on the selected page. During writing, only those
dots are switched on that correspond to "1"-bits. To focus on another page in
the same column, the lens is moved perpendicular to the FMC plane. To
20 focus on another page in the same layer, the Clear Card itself is moved.
A possible version of apparatus with parallel (page by page) data
recording and retrieval on Clear Cards is shown in Fig. 2. Recording of
information on pages in FMC photosensitive layers is enabled through the use
of LED or VCSEL matrix 21 as a light source. The matrix is driven by
25 microelectronic IC 22 controlled by computer 23. The number and disposition
of Leds (VCSELs) in the matrix corresponds to the number and disposition of
information pits on one FMC page. During writing, LEDs (VCSELs)
corresponding to "1" pits are switched on. The reduced image of the light-
emitting dot matrix is generated on the desired FMC page by aspheric lens
30 24. To write information on another page in the same layer, the clear card
itself is moved by actuator 26 in X- or Y-direction.
To ensure reasonable power consumption of the light-emitting dot
matrix and reasonable size of the entire device, divergence of the beam in
each emitter should be small enough. The VCSEL having a diffraction-limited
output beam meets this requirement. The LED matrix needs a corresponding
micro lens matrix to condense output emission.
5 For example, if the diameter of each information pit is 0.5 |Lim, the spatial
period of pits disposition in the 500x500 page is 1 lutm and the magnification of
the optical system is x20, then the diameter of each emitter is 1 0 [j,m and its
size is 1 .0x1 .0 cm. The total number of emitters (pits) is 250 000.
For VCSELs of visible spectral range with a 10-|am aperture, the beam
10 divergence depending on the wavelength is several angular degrees. To form
similar beam divergence of LED a condensing micro lens is required. The
condensing LED diameter must be significantly smaller than the lens diameter
(10 \xm in this example). The best specimens if visible LEDs having their
external efficiency of more than 1 0% permits obtaining about 1 00 nW CW
15 output power from 2 |Ltm in diameter emitting surface. The matrix of such
LEDs with 20-micron spatial period integrated with corresponding matrix of
micro lenses of 10-micron diameter meets the requirements for the proposed
apparatus. Assuming even 90% loss in the optical system, it corresponds to
1 0 nW per pit (about 5W/cm^). For photosensitive material with the absorption
20 cross-section of 1 0'^® cm^, such power density of illumination permits one to
obtain a recording bit rate of about 1 Gbit/sec using the proposed method.
The total power consumption of the LED matrix in this case will be of
the order of 0.1 0 W. Taking into account its size, no special cooling system is
25 The theoretical estimations show that using this method and
photosensitive materials with linear response, information can be written in
FMC-R containing up to 1 0 layers. For materials there are practically no
limitations for the number of layers.
Written information can be retrieved page by page. To initiate
30 fluorescence one column of pages is illuminated by emission from light source
(laser or LED) 27 of the appropriate wavelength. If necessary 100% mirror 28
can be used. The magnified image of the needed page is formed on the
receiving surface of CCD camera 29 using lens 24 and semitransparent
mirror 200. To obtain maximum contrast of the CCD camera output signal,
the illuminating emission must be filtered. For this purpose dichroic mirror 201
5 with an appropriate spectral pass band may be used. The fluorescent
emission from pits is not polarized. Another possibility to filter illuminating
emission of pits is to use a polarizer instead of mirror 201 . If the illuminating
beam is not fully polarized another crossed polarizer can be inserted (not
shown in Fig.2).
10 The necessary condition in this case is isotropism of the molecules
disposed in the FMC information marks to ensure luminescence isotropism
even under the action of polarized reading radiation. In this case the reading
beam incident on the photo receiver will be switched off (absorbed) by the
analyzer while partially absorbed nonpolarized luminescent radiation will pass
15 via the analyzer to the photoreceiver.
Another possibility is to apply a Notch liquid crystal filter as spectral
One more version of random-access light-emitting dot matrix is
schematically shown in Fig. 3.
20 The controllable light-emitting matrix can be also implemented on the
basis of microoptoelectromechanical system (MOEMS) representing a matrix
of micro mirrors 30 with electrically controllable position on the corresponding
piezo crystal matrix. Said matrix in turn is integrated with electronic control
circuit 31. Depending on the driving signal from computer 32, in matrix
25 elements the mirrors that have received signal "1" are disposed at a different
angle as compared to the mirrors that have received signal "0". If said matrix
is illuminated by a parallel light beam, then lens 33 of the above-mentioned
system can be positioned in such a way that only beams reflected from the
matrix elements that received signal "1" will get in the aperture.
30 Coming back to the geometry and power assessments of the example
discussed above and assuming that the mirrors occupy 25% of the total
matrix area and have their reflection coefficient about 100%, it follows that to
achieve 10 nW/pit in the recording mode, a 150 mV homogeneous uniform
light beam about 15 cm in diameter will be needed. To this end, many laser
types of different spectral ranges can be utilized. In particular, there exist
5 miniature laser diodes enabling the above-mentioned CW power in spatial
single-mode operation. To generate the requisite beam, beam circularizer-
expander 35 should be placed behind laser 34.
While the above description contains many specificities, these should
not be construed as limitations on the scope of the invention, but rather as
10 exemplification of the preferred embodiments. Those skilled in the art will
envision other possible variations that are within its scope. Accordingly, the
scope of the invention should be determined not by the embodiment
illustrated, but by the appended claims and their legal equivalents.
WHAT IS CLAIMED IS:
1 . An apparatus for recording and retrieval of information on/from the
fluorescent optical card comprising
-a card holder;
-a device for moving the cards relative to the writing/reading beams;
-a controllable light-emitting dot matrix for writing information on the
-an illuminating light source for reading information from the card;
-a photoreceiver for reading information from the card; and
-an optical system to form an image of light-emitting dot matrix on the
information pages of the card and to form an image of the information pages
of the card on the input surface of the photoreceiver,
2. The apparatus of claim 1 , wherein recording of information is
produced in parallel mode of operation (page by page).
3. The apparatus of claims 1 and 2, wherein the random-access light-
emitting dot matrix is used as a light source for recording information.
4. The apparatus of claims 1 and 3, wherein the number and
disposition of dots in the light-emitting dot matrix corresponds to the number
and disposition of information pits on one page of the card.
5. The apparatus of claims 1 , 3 and 4, wherein the light-emitting diode
(soiid-state or organic) matrix is used as a light-emitting dot matrix.
6. The apparatus of claims 1 and 5, wherein the light-emitting diode
matrix is integrated with the driving microelectronic integral circuitry and matrix
of condensing micro lenses.
7. The apparatus of claims 1 , 3 and 4, wherein the matrix of vertical
cavity surface emitting lasers is used as a light-emitting dot matrix.
8. The apparatus of claims 1 , 3 and 4, wherein said matrix of vertical
cavity surface-emitting lasers is integrated with the driving microelectronic
9. The apparatus of claims 1 , 3 and 4, wherein the laser and
controllable transparency are used as a light-emitting dot matrix.
1 0. The apparatus of claims 1 , 3 and 4, wherein the laser or
controllable matrix of micro mirrors is used as a light-emitting dot matrix.
1 1 . The apparatus of claim 1 , wherein the actuator-controlled lens
forms the image of said light-emitting dot matrix on the selected page of the
12. The apparatus of claim 1, wherein during the recording process
only those light-emitting dots are switched on that correspond to "1"-bits.
1 3. The apparatus of claim 1 1 , wherein switching over to the other
page in the same column is provided by lens moving perpendicular to the card
14. The apparatus of claims 1 and 1 1 , wherein switching over to the
other page in the same column is provided by moving of the card itself in the
perpendicular to the optical axis of lens direction.
15. The apparatus of claim 1 , wherein the retrieval of information is
produced in parallel operation mode (page by page).
16. The apparatus of claim 1 , wherein the coupled charge device
camera is used as a photoreceiver.
17. The apparatus of claim 1 , wherein the illuminating light during
information retrieval is filtered to ensure that only fluorescent (information
carrying) light reaches the photoreceiver.
1 8. The apparatus of claims 1 and 1 7, wherein the dichroic mirror Is
used as a spectral filter.
19. The apparatus of claims 1 and 17, wherein the Notch filter based
on liquid crystals is used as a spectral filter.
20. The apparatus of claims 1 and 17, wherein polarizer(s) is (are)
used for filtering the illuminating light.