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(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) 



(19) World Intellectual Property Organization 

International Bureau 




llllllllllllllllllllllllllllllllllllllllllllllllll 



(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, 



7/125 

(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: 

60/251,580 



(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 
(RU). 



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). 

Published: 

— 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. 



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1 



APPARATUS FOR RECORDING ON AND/OR RETRIEVAL 
FROM FLUORESCENT OPTICAL CLEAR CARD 

5 

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. 



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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 



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3 



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 

25 

Below a description of the present invention is given with reference to 
accompanying drawings. 

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. 



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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 

25 compounds. 

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, 



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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 
FMC volume. 

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 



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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 
necessary. 

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 



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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. 

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 



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8 

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. 

15 



20 



25 



30 



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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 

card; 

-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 
integral circuitry. 



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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 
card. 

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 
plane. 

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. 



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Fig.2 



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Fig.5