US007226637B2 (12) United States Patent (10) Patent No.: US 7,226,637 B2 Dorozhkina et al. (45) Date of Patent: Jun. 5, 2007 (54) MANUFACTURING METHOD FOR (56) References Cited MULTILAYER FLUORESCENT INFORMATION CARRIERS U.S. PATENT DOCUMENTS 4,407,855. A * 10/1983 Russell ....................... 427,512 (75) Inventors: Galina Dorozhkina, Dolgoprodni 5,120,811 A 6/1992 Glotfelter et al. ............. 528/25 (RU); Irina Kiryusheva, Tel-Aviv (IL); 5,194.490 A * 3/1993 Suga et al. ....... ... 524/755 s Kiry s y 5,688.447 A 1 1/1997 Hong ........................ 264/1.33 Eugene Levich, New York, NY (US); 5,801,884 A * 9/1998 Sato et al. .................. 359/620 Alexey Lezhnev, Moscow (RU); 6,023,451 A 2/2000 Kashiwagi et al. ...... 369/2755 Dmitry Pebalk, Moscow (RU) 6,039,898 A 3/2000 Glushko .................... 264/1.33 6,071,671 A * 6/2000 Glushko et al. ....... 430,270.15 (73) Assignee: D Data Inc., New York, NY (US) 6,355,754 B1* 3/2002 Olson et al. ................ 526,296 6,368,684 B1 * 4/2002 Onishi et al. .............. 428, 32.6 (*) Notice: Subject to any disclaimer, the term of this 2002/0066528 A1* 6/2002 Oxman et al. ........... 156/2755 patent is extended or adjusted under 35 FOREIGN PATENT DOCUMENTS U.S.C. 154(b) by 542 days. EP O 913 444 A2 5, 1999 JP O3-173954 A * 7, 1991 (21) Appl. No.: 09/761,647 WO WO 98.50914 11, 1998 WO WO 99,23652 5, 1999 (22) Filed: Jan. 18, 2001 WO WO 99/47327 9, 1999 * cited by examiner (65) Prior Publication Data Primary Examiner Alain L. Bashore US 2001/OO48977 A1 Dec. 6, 2001 (74) Attorney, Agent, or Firm Winston & Strawn LLP (57) ABSTRACT Related U.S. Application Data An information layer for an optical information storage (60) Provisional application No. 60/176,294, filed on Jan. medium is formed in a centrifuge. A photopolymerizable 18, 2000. composition is applied to a solid base having a relief pattern, and a flexible, transparent film layer is applied on top of the (51) Int. Cl. composition. The three are spun in a centrifuge to cause a B05C 5/06 (2006.01) thin, even distribution of the photopolymerizable composi (52) U.S. Cl. ...................... 427/162; 427/164; 427/240; tion, which is photopolymerized. The resulting replica is 427/425; 427/508; 427/510; 427/512; 427/157; separated from the relief pattern and has a fluorescent 118/52; 118/319; 118/320; 369/272.1; 369/275.3: material applied thereto. Alternatively, the replica has a 369/283; 369/284; 369/286; 369/288; 369/94 non-fluorescent material applied thereto, and the non-fluo (58) Field of Classification Search ................ 427/508, rescent material is made fluorescent through diffusion. Mul 427/510,512, 157, 162, 164, 240, 425; 118/52, tiple information layers thus formed can be glued together to 118/319, 320, 369/272.1, 275.3, 283, 284, form a multilayer optical information storage medium. 369/286, 288,94 See application file for complete search history. 21 Claims, 3 Drawing Sheets Sl 4. Zaaya Za Zaya Zaza Zaza 1272 } 6 say a NaNNNaa Naa NS N a 777.2777777.772/7ZZZZZZ 3b N C Y aw a YYYYYYN NSNS 2 N 2 2 2 U.S. Patent Jun. 5, 2007 Sheet 1 of 3 US 7,226,637 B2 2 2 2 FIG. 1 3 S-2 . N 2 FIG. 2 U.S. Patent Jun. 5, 2007 Sheet 2 of 3 US 7,226,637 B2 4 2. NSN 3b 2 1- N 2 FIG. 4 U.S. Patent Jun. 5, 2007 Sheet 3 of 3 US 7,226,637 B2 3b //ZZZZZZZZZZZZZZZZZZZZ FIG. 5 ZZZZZZZZZZZZZZZZZZZZZZavaaraaaavaaraavaaraavanauaaaaaa-Navy YYYAas 10 VNarvyvvvvvavvvyZZZZZZZZZZZZZZZZZZZZZZ ArvyAAAAAYAAAAYAA 2. FIG. 6 12 1la 13 ZZYZZZZZZZZZZZZZ23,772/7212,772 ZZ777 11 FIG. 7 US 7,226,637 B2 1. 2 MANUFACTURING METHOD FOR fluorescent information carrier in which a relief-carrying MULTILAYER FLUORESCENT layer made of liquid photopolymerizing composition (PPC) INFORMATION CARRIERS is formed between a solid base disposed directly on a chuck and an overlying flexible film material, either of which REFERENCE TO RELATED APPLICATIONS 5 should be actinic-radiation-transparent, and either of which can act as a stamper. Under the action of centrifugal forces, This application claims the benefit of U.S. Provisional the relief-carrying layer is photo-solidified by light of a Application No. 60/176,294, filed Jan. 18, 2000, whose spectral range requisite for photopolymerization and sepa disclosure is hereby incorporated by reference in its entirety rated from the stamper. The relief-carrying layer is then into the present disclosure. 10 filled with a liquid composition with a fluorescent dye. The composition is photosolidified. Single-layer film fluorescent FIELD OF THE INVENTION information carriers thus formed are arranged in a multilayer block via adhesive, cementing layers to obtain a multilayer The present invention is directed to a method of manu fluorescent information carrier. facturing a multilayer fluorescent information carrier and 15 more particularly to such a method in which materials are BRIEF DESCRIPTION OF THE DRAWINGS applied under the action of centrifugal forces. Various preferred embodiments of the present invention DESCRIPTION OF RELATED ART will be set forth in detail with reference to the drawings, in which: In digital storage, whether of Software, music, motion FIG. 1 shows a solid base placed on a centrifuge chuck; pictures, or the like, it has long been desired to store ever FIG. 2 shows the application of liquid photopolymeric more information in ever less space. Compact discs have composition to the base to form a layer; been in use for roughly two decades to store music, software, FIG. 3 shows irradiation of the layer with photopolymer and other materials in digital form. However, the fact that a 25 izing light; compact disc has only one recording layer limits its infor mation capacity. FIG. 4 shows the removal of the resulting replica; To increase the capacity relative to a traditional compact FIG. 5 shows formation of an information layer from the disc, optical memory media with multiple layers have been replica; developed. However, when such media are read by reflection 30 FIG. 6 shows formation of a multilayer medium from of coherent light, parasitic reflection can occur at layer multiple information layers; and boundaries. That reflection and the resulting interference FIG. 7 shows an alternative technique for formation of an impair reading. information layer from the replica. One such device is the multilayer fluorescent information DETAILED DESCRIPTION OF THE carrier, examples of which are disclosed in U.S. Pat. No. 35 6,039,898, issued Mar. 21, 2000, and in WO99/47327 A1, PREFERRED EMBODIMENTS published Sep. 23, 1999. Such carriers exhibit high record ing density, contrast, and signal-to-noise ratio. It is common The manufacturing process for the relief-carrying layer to use fluorescent recording materials that, when exposed to will be described with reference to FIGS. 1-6, with an reading light at one wavelength, fluoresce at a different 40 alternative technique disclosed with reference to FIG. 7. wavelength. The problem of parasitic reflection can be Then, specific examples will be given. solved by filtering out reflected light at the reading wave The procedure takes place in a centrifuge having a cen length. Also, since the fluorescent light is incoherent, there trifuge chuck 1. As shown in FIG. 1, a solid base 2 is placed is no problem of interference. on the centrifuge chuck 1. Optically transparent glass or However, improvements remain to be made in the manu 45 polymer, including multilayer Substrates with pre-fabricated facture of such carriers. In particular, it would be desirable ILS, and nontransparent materials, including metal, glass or to decrease both the thickness and the thickness variation of polymer Substrates, can be used as a solid base. The Solid the recording layers while increasing production speed and base 2 has surface details (a relief pattern) 2a as required to improving the information reproduction characteristics. form the relief-carrying layer. 50 As shown in FIG. 2, a liquid photopolymeric composition SUMMARY OF THE INVENTION (PPC) 3 is put onto the solid base 2. Then, as shown in FIG. 3, a flexible film material 4 is applied. Either the solid base In light of the above, it is an object of the invention to 2 or the flexible film material 4 can serve as a stamper; that decrease the thickness of the relief-carrying information is, either the solid base or the flexible material can have the layer. 55 required surface relief 2a. The centrifuge chuck 1 is rotated It is another object of the invention to decrease the layer to cause the PPC to form a thin, uniform layer 3a through thickness variation. centrifugal force. Through varying speed, rotation time, It is another object of the invention to speed up the viscosity and PPC wettability, conditions are selected for formation process for both a single layer and a multilayer fabricating a thin, uniform PPC layer 3a between the solid structure through consecutive building-up information lay 60 base 2 and flexible material 4. ers (IL). After the layer 3a with specified thickness has been It is another object of the invention to increase the formed, it is irradiated by light 5 with a spectral range fluorescent signal and its contrast, enabling an increase in appropriate for photopolymerization, thereby photopoly the fluorescent carrier information capacity to reduce the merizing the layer 3a to form a photopolymerized layer 3b. requirement for a larger number of layers. 65 Then, as shown in FIG.