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United States Patent m
 COMPOSITE ARTICLE COMPRISING ORIENTED MICRO STRUCTURES
 Inventor: Mark K. Debe, Stillwater, Minn.
 Assignee: Minnesota Mining and
Manufacturing Company, St. Paul,
 Appl. No.: 720,188
 Filed: Jun. 24, 1991
 Int. CI.5 B32B 5/16
 U.S. CI 428/323; 428/327;
428/357; 428/378; 428/409
 Field of Search 428/323, 327, 378, 409,
428/411.1, 357, 149, 143, 179, 325; 156/247;
204/192.14, 192.26; 427/255.6
 References Cited
U.S. PATENT DOCUMENTS
3,220,897 11/1965 Conley et al 148/34
3,293,109 12/1966 Luce et al 161/166
3,585,010 6/1971 Luce et al 29/191.2
3,969,545 7/1976 Slocum 427/163
4,002,541 1/1977 Streander 204/33
4,148,294 4/1979 Scherber et al 126/270
4,155,781 5/1979 Diepers 148/175
4,209,008 6/1980 Lemkey et al 126/452
4,215,170 7/1980 Oliva 428/328
4,252,843 2/1981 Dorer 427/162
4,252,865 2/1981 Gilbert et al 428/611
4,340,276 7/1982 Maffitt et al 350/164
4,396,643 8/1983 Kuehn et al 427/160
4,410,565 10/1983 Kitamoto et al 427/130
4,560,603 12/1985 Giacomel 428/86
4,568,598 2/1986 Bilkadi et al 428/141
4,588,656 5/1986 Kitamoto et al 428/694
4,678,695 7/1987 Tung et al 428/120
4,774,122 9/1988 Adler 428/156
4,812,352 3/1989 Debe 428/142
4,908,258 5/1990 Hernandez 428/198
FOREIGN PATENT DOCUMENTS
0070102 1/1983 European Pat. Off. G03F 1/00
0102204 3/1984 European Pat. Off. H01L 31/02
3446243 6/1986 Fed. Rep. of Germany F28F
[ii] Patent Number: 5,336,558  Date of Patent: Aug. 9,1994
Japanese Abstract for No. 57-148138, Sep. 13, 1982. U.S. patent application Ser. No. 07/271,930, filed Nov. 14, 1988 (Debe).
U.S. patent application Ser. No. 07/681,332, filed Apr. 5, 1991, entitled "Sensors Based on Nanostructured Composite Fibers" (Debe).
J. Vac. ScL Technol. A, 5, (4), Jul./Aug., 1987, pp. 1914-1916, K. K. Kam, M. K. Debe, R. J. Poirier, and A. R. Drube.
J. Vac. ScL Technol. A, 6, (3), May/Jun., 1988, pp. 1907-1911, M. K. Debe, K. K. Kam, J. C. Liu, and R. J. Poirier.
Thin Solid Films, 186, 1990, pp. 327-347, M. K. Debe and R. J. Poirier.
J. Mat. ScL, 25, 1990, pp. 5257-5268, Y. Sadaoka, T. A. Jones, G. S. Revell, W. Gopel.
Thin Solid Films, 47,1977, pp. 219-233, A. G. Dirks and H. J. Leamy.
Rapidly Quenched Metals (Proc. of the Fifth Int. Conf. on Rapidly Quenched Metals, Wurzburg, Germany, Sep. 3-7, 1984), pp. 1117-1124, 1985, S. Ohnuma, Y. Nakanouchi & T. Masumoto.
J. Vac. ScL Technol B, 8, (6), Nov./Dec, 1990, pp. 1199-1211, G. S. Oehrlein, J. F. Rembetski, and E. H. Payne.
J. Vac. ScL Technol. A, 1, (3), Jul./Sep., 1983, pp. 1398-1402 J. A. Floro, S. M. Rossnagel, and R. S. Robinson.
Photo. ScL and Eng., 24, (4), Jul./Aug., 1980, pp. 211-216, P. K. Lee and M. K. Debe.
Primary Examiner—Paul J. Thibodeau
Assistant Examiner—H. Thi Le
Attorney, Agent, or Firm—Gary L. Griswold; Walter N.
Kirn; Gregory D. Allen
This invention provides a composite article having discrete microstructures partially encapsulated within a layer. A method of making the same is also provided. The article of the present invention is useful for visible radiation absorbing devices, such as, for example, selective solar absorbers, flat plate solar collectors, solar absorption panels, and solar cells.
37 Claims, 2 Drawing Sheets
U.S. Patent Aug. 9,1994 sheet 2 of 2 5,336,558
COMPOSITE ARTICLE COMPRISING ORIENTED
FIELD OF THE INVENTION 5
This invention relates to a composite article comprising uniformly or randomly oriented microstructures partially encapsulated within a layer. In another aspect, this invention relates to a method of making the same.
BACKGROUND OF THE INVENTION
Composite articles containing or exhibiting a microstructured layer or columnar-structured layer have been disclosed in the art.
For example, Kitamoto et al. U.S. Pat. No. 4,410,565" discloses an article said to be useful as a magnetic recording medium, the article comprising a substrate, a thermoplastic prime-coating layer provided thereon, a ferromagnetic metal layer having columnar grains ^ which at least partially penetrate into the prime coat from the top thereof and are integrated therewith. A method of making the same is also disclosed. Further, U.S. Pat. No. Kitamoto et al. 4,588,656 teaches a method of preparing an article said to be useful as a 2« magnetic recording medium, the method comprising vapor depositing a thin ferromagnetic metal film having spaced-apart columnar grain structures onto a substrate, impregnating the spaces between the columnar grain structures with at least one organic monomer or oligomer in the liquid form, and polymerizing the monomer or oligomer at least in the spaces between the columnar grain structures, whereby the resulting polymer is integrated with the thin ferromagnetic metal film.
Giacomel U.S. Pat No. 4,560,603 teaches a method 35 for making a high strength laminated composite-structured material comprising the steps of (a) providing whiskers having a characteristically preferred orientation in an electromagnetic field, (b) placing fibers in a substantially overlapping relationship having viscous 40 material therebetween to form a composite matrix, (c) disposing the whiskers in the viscous material, (d) applying a magnetic field about the whiskers in a shape effective to selectively orient the whiskers in a preferred direction, and (e) curing the composite matrix to 45 form a laminate, while at the same time retaining the whiskers in the desired direction.
Adler U.S. Pat. No. 4,774,122 discloses a resinous product having a resinous surface which is coatable with a metal layer so as to be bonded through an array 50 of microdendrites. A method of making the same is also disclosed.
U.S. Pat. No. 4,812,352 and assignee's U.S. patent application, Ser. No. 07/271,930, filed Nov. 14, 1988, now Debe U.S. Pat. No. 5,039,561 teach an article com- 55 prising a substrate bearing a microlayer (microstructured-layer)which comprises uniformly oriented, crystalline, solid, organic nanometer-sized microstructures and a method of making the same. Further, U.S. Pat. Nos. 4,812,352 and U.S. Ser. No. 07/271,930 teach op- 60 tionally conformal coating the microlayer and encapsulating the conformal-coated microlayer.
Kam et al. in "Summary Abstract: Dramatic Variation of the Physical Microstructure of a Vapor Deposited Organic Thin Film" J. Vac. ScL Technol. A, 5, (4), 65 July/August, 1987, pp. 1914-16, teach a vacuum deposition method for making organic microstructures (or whiskers).
Debe et al, in "Vacuum Vapor Deposited Thin Films of a Perylene Dicarboxide Derivative: Microstructure Versus Deposition Parameters" J. Vac. ScL Technol. A, 6, (3), May/June, 1988, pp. 1907-11, teach a vacuum vapor deposition method for generating organic microstructures.
Debe et al. in "Effect of Gravity on Copper Phthalocyanine Thin Films III: Microstructure Comparisons of Copper Phthalocyanine Thin Films Grown in Microgravity and Unit Gravity" Thin Solid Films, 186, 1990, pp. 327-47, disclose organic microstructured surfaces grown by physical vapor transport in microgravity and on the earth's surface.
Sadaoka et al. in "Effects of Morophology on NO2 Detection in Air at Room Temperature with Phthalocyanine Thin Films", J. Mat. ScL, 25, 1990, pp. 5257-68, teach a method of growing nickel phthalocyanine whiskers by annealing a film of the same in air.
Dirks et al. in "Columnar Microstructure in VaporDeposited Thin Films", Thin Solid Films, 47, 1977, pp. 219-33, review methods known in the art for making columnar microstructures.
Slocum U.S. Pat. No. 3,969,545 discloses a vacuum deposition technique for making organic or inorganic microstructures. The microstructured surface is said to have excellent polarization characteristics over wavelengths from the visible to the infrared region.
Ohnuma et al. in "Amorphous Ultrafine Metallic Particles Prepared By Sputtering Method", Rapidly Quenched Metals, (Proc. of the Fifth Int. Conf. on Rapidly Quenched Metals, Wurzburg, Germany, Sept. 3-7, 1984), S. Steeb et al., eds., Elsevier Science Publishers B.V., New York, (1985), pp. 1117-24, teach microstructured surfaces made using ion etching and rf sputter etching of polymer surfaces.
Bilkadi et al. U.S. Pat. No. 4,568,598 teaches a composite sheet-like article comprising surface ridges or needles of amplitude in the range of 0.1 to 5.0 micrometers and a separation of their axes in the range of 0.01 to 1.0 micrometer and having an aspect ratio in the range of 0.01 to 10 micrometers.
Maffitt et al. U.S. Pat. No. 4,340,276 discloses a method for making a microstructure on the surface of an article, the method comprising the steps of depositing a discontinuous coating of a material exhibiting a low rate of sputter etching and differentially sputter etching the composite surface to produce a topography of pyramid-like micropedestals random in height and separation.
Oehrlein et al. in "Study of Sidewall Passivation and Microscopic Silicon Roughness Phenomena in Chlorine-Based Reactive Ion Etching of Silicon Trenches", /. Vac. ScL Technol. B, 8, (6), Nov./Dec, 1990, pp. 1199-1211, teach patterned structures using photolithographic and reactive ion etching methods.
Floro et al. in "Ion-Bombardment-Induced Whisker Formation On Graphite" /. Vac ScL Technol, A, 1, (3), July-Sept., 1983, pp. 1398-1402, disclose graphite whisker-like structures produced by an ion bombardment process.
Gilbert et al. U.S. Pat. No. 4,252,865, teaches a solar energy absorbing surface, the surface characterized by having an array of outwardly projecting structural elements of relatively high aspect ratio and having effective lateral spacings which are or include those in the order of magnitude of wavelengths within the solarenergy spectrum. The disclosed method for making the