WO1998058749A1 - Controlled laser texturing glass-ceramic substrates for magnetic recording media - Google Patents
Controlled laser texturing glass-ceramic substrates for magnetic recording media Download PDFInfo
- Publication number
- WO1998058749A1 WO1998058749A1 PCT/US1997/012198 US9712198W WO9858749A1 WO 1998058749 A1 WO1998058749 A1 WO 1998058749A1 US 9712198 W US9712198 W US 9712198W WO 9858749 A1 WO9858749 A1 WO 9858749A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- glass
- ceramic substrate
- substrate
- crystalline phase
- less
- Prior art date
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C23/00—Other surface treatment of glass not in the form of fibres or filaments
- C03C23/0005—Other surface treatment of glass not in the form of fibres or filaments by irradiation
- C03C23/0025—Other surface treatment of glass not in the form of fibres or filaments by irradiation by a laser beam
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
- B05D5/12—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain a coating with specific electrical properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
- B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
- G11B5/739—Magnetic recording media substrates
- G11B5/73911—Inorganic substrates
- G11B5/73921—Glass or ceramic substrates
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
- G11B5/8404—Processes or apparatus specially adapted for manufacturing record carriers manufacturing base layers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S428/00—Stock material or miscellaneous articles
- Y10S428/90—Magnetic feature
Definitions
- the present invention relates to the recording, storage and reading of magnetic data, particularly rotatable magnetic recording media, such as thin film magnetic disks having textured surfaces for contact with cooperating magnetic transducer heads.
- the invention has particular applicability to high density magnetic recording media for mobile computer data storage applications .
- Thin film magnetic recording disks and disk drives are conventionally employed for storing large amounts of data in magnetizable form.
- one or more disks are rotated on a central axis in combination with data transducer heads.
- a typical contact start/stop (CSS) method commences when the head begins to slide against the surface of the disk as the disk begins to rotate. Upon reaching a predetermined high rotational speed, the head floats in air at a predetermined distance from the surface of the disk due to dynamic pressure effects caused by air flow generated between the sliding surface of the head and the disk.
- the transducer head During reading and recording operations, the transducer head is maintained at a controlled distance from the recording surface, supported on a bearing of air as the disk rotates, such that the head can be freely moved in both the circumferential and radial directions allowing data to be recorded on and retrieved from the surface of the disk at a desired position.
- the rotational speed of the disk decreases and the head again begins to slide against the surface of the disk and eventually stops in contact with and pressing against the disk.
- the transducer head contacts the recording surface whenever the disk is stationary, accelerated from the stop and during deceleration just prior to completely stopping.
- the sliding surface of the head repeats the cyclic operation consisting of stopping, sliding against the surface of the disk, floating in the air, sliding against the surface of the disk and stopping.
- each transducer head it is considered desirable during reading and recording operations to maintain each transducer head as close to its associated recording surface as possible, i.e., to minimize the flying height of the head.
- a smooth recording surface is preferred, as well as a smooth opposing surface of the associated transducer head, thereby permitting the head and the disk to be positioned in close proximity with an attendant increase in predictability and consistent behavior of the air bearing supporting the head.
- the precision match of these surfaces gives rise to excessive stiction and friction during the start up and stopping phases, thereby causing wear to the head and recording surfaces eventually leading to what is referred to as a
- Conventional practices for addressing these apparent competing objectives involve providing a magnetic disk with a roughened recording surface to reduce the head/disk friction by techniques generally referred to as "texturing.”
- texturing techniques involve polishing the surface of a disk substrate to provide a texture thereon prior to subsequent deposition of layers, such as an underlayer, a magnetic layer, a protective 2 overcoat, and a lubricant topcoat, wherein the textured surface on the substrate is intended to be substantially replicated in the subsequently deposited layers.
- a typical magnetic recording medium is depicted in Fig. 1 and comprises a substrate 10, typically an aluminum (Al) -base alloy, such as an aluminum-magnesium
- Al-Mg amorphous nickel - phosphorous alloy
- NiP nickel - phosphorous
- substrate 10 a chromium (Cr) or Cr-alloy underlayer 11
- a magnetic layer 12 which is usually a cobalt (Co) -base alloy
- a protective overcoat 13 which usually comprises carbon
- a lubricant topcoat 14 Cr or Cr-alloy underlayer 11, Co-base alloy magnetic layer 12 and protective carbon overcoat 13 are typically deposited by sputtering techniques.
- a conventional Al- alloy substrate is provided with a NiP plating primarily to increase the hardness of the Al substrate, serving as a suitable surface for polishing to provide the requisite surface roughness or texture, which is intended to be substantially replicated on the disk surface.
- the escalating requirements for high areal recording density impose increasingly greater requirements on thin film magnetic media in terms of coercivity, stiction, squareness, low medium noise and narrow track recording performance.
- increasingly high density and large-capacity magnetic disks require increasingly smaller flying heights, i.e., the distance by which the head floats above the surface of the disk in the CSS drive. The requirement to further reduce the flying height of the transducer head renders it particularly difficult to satisfy the requirements for controlled texturing to avoid head crash.
- Conventional techniques for providing a disk substrate with a textured surface comprise a mechanical operation, such as polishing. See, for example, Nakamura et al . , U.S. Patent No. 5,202,810.
- Conventional mechanical texturing techniques are attendant with numerous disadvantages. For example, it is extremely difficult to provide a clean textured surface due to debris formed by mechanical abrasions. Moreover, the surface inevitably becomes scratched during mechanical operations, which contributes to poor glide characteristics and higher defects.
- various desirable substrates are difficult to process by mechanical texturing. This undesirably limiting facet of mechanical texturing, virtually excludes the use of many materials for use as substrates.
- An alternative texturing technique to mechanical texturing comprises the use of a laser light beam focused on an upper surface of a non-magnetic substrate. See, for example, Ranjan et al . , U.S. Patent No. 5,062,021, wherein the disclosed method comprises polishing an NiP plated Al substrate to a specular finish, and then rotating the disk while directing pulsed laser energy over a limited portion of the radius, to provide a textured landing zone leaving the data zone specular.
- the landing zone comprises a plurality of individual laser spots characterized by a central depression surrounded by a substantially circular raised rim.
- the bottom of the depression flattens into a rounded, smooth, central dome resembling a "sombrero."
- the central dome broadens and decreases in height to eventually become equal to or lower than the rim.
- a laser texturing technique employing a multiple lens focusing system for improved control of the resulting topographical texture.
- a laser texturing technique is disclosed wherein a pulsed, focused laser light beam is passed through a crystal material to control the spacing between resulting protrusions.
- U.S. Patent No. 5,273,834 discloses the use of alternate substrates, such as glass-ceramic substrates.
- the substrate material is provided with ions for absorbing radiation in the near infrared portion of the spectrum, thereby rendering the material capable of attaining elevated temperatures during film deposition.
- the use of heat treatment to form a textured surface on alternate substrates, such as glass or glass-ceramic substrates, is undesirably slow and inefficient in terms of energy consumption. Significantly, it is extremely difficult to exercise control over the size and shape of the secondary crystal grains due to inherent limitations in controlling temperature uniformity.
- the resulting texture comprises irregularly shaped protrusions with surrounding valleys extending into the substrate, thereby creating undesirable stress profiles during subsequent deposition of layers by sputtering at elevated temperatures . Such undesirable stress profiles render it extremely difficult to accurately replicate the texture in subsequently deposited layers.
- a method for laser texturing a glass or glass-ceramic substrate employing a laser light beam derived from a C0 2 laser source.
- the textured glass or glass-ceramic substrate surface comprises a plurality of protrusions which extend above the substrate surface, without surrounding valleys extending substantially into the substrate as is characteristic of a laser textured metallic substrate.
- the effect of laser parameters, such as pulse width, spot size and pulse energy, and substrate composition on the protrusion or bump height of a laser textured glass or glass-ceramic substrate is reported by Kuo et al .
- An object of the present invention is a magnetic recording medium comprising a glass-ceramic substrate having an accurately controlled topographical texture.
- Another object of the present invention is a method of laser texturing a glass-ceramic substrate by controlling the height of the resulting protrusions formed on the substrate surface and reducing the sensitivity of the protrusion height to pulse energy.
- a method of manufacturing a magnetic recording medium comprises: texturing a surface of a glass-ceramic substrate with a pulsed, focused laser light beam to form a plurality of protrusions on and extending above the substrate surface; wherein the crystalline phase of the glass-ceramic substrate is less than about 70% by volume, for example, below about 50% by volume.
- Another aspect of the present invention is a method of manufacturing a magnetic recording medium, which method comprises: texturing a surface of a glass-ceramic substrate with a pulsed, focused laser light beam to form a plurality of protrusions on and extending above the substrate surface; and controlling the height of the protrusions by controlling the amount of crystalline phase of the glass-ceramic substrate under about 70% by volume, for example, below about 50% by volume.
- a further aspect of the present invention is a magnetic recording medium comprising: a non-magnetic glass-ceramic substrate having an upper surface; and a magnetic layer on the upper surface; wherein: the upper surface contains a textured landing zone comprising a plurality of protrusions of secondary crystals grown on the upper surface by a focused, pulsed laser light beam; and the glass-ceramic substrate comprises less than about 70% by volume of crystalline phase.
- Fig. 1 schematically depicts a conventional magnetic recording medium structure.
- Fig. 2 schematically depicts a laser texturing system in accordance with an embodiment of the present invention.
- Fig. 3 schematically depicts a magnetic recording medium structure in accordance with the present invention.
- Fig. 4 compares protrusion height and pulse energy for glass-ceramic substrates having different amounts of crystalline phase.
- Fig. 5 depicts the bump diameter and pulse energy relationship for glass-ceramic substrates having different amounts of crystalline phase. Description of the Invention
- the resulting topographical texture comprises a plurality of rounded protrusions extending above the substrate surface, without surrounding valleys extending substantially into the substrate as in texturing a metal -containing surface, such as an NiP plated Al or Al -alloy substrate.
- a metal -containing surface such as an NiP plated Al or Al -alloy substrate.
- Such relatively uniform protrusions improve the tribological performance of the resulting magnetic recording medium, by enabling the independent optimization of surface topography in each of the landing zone and data zone.
- the height of the protrusions is one of the most critical parameters in that it directly impacts glide and tribological performance. Protrusion height is dependent upon several factors, including spot size, pulse width and pulse energy. Accordingly, the present invention comprises a method of laser texturing a glass-ceramic substrate wherein the height of the resulting protrusions extending above the substrate surface is controlled to optimize glide and tribological performance.
- the overall protrusion height is reduced and the sensitivity of protrusion height to pulse energy is further reduced by controlling the amount of crystalline phase in the glass-ceramic substrate material subject to laser texturing.
- the amount of crystalline phase of a glass-ceramic substrate is controlled under about 70% by volume, for example, less than about 50% by volume, even less than about 30% by volume.
- the glass-ceramic substrate employed in the practice of the present invention typically has a density less than about 2.44 g/cc, for example, below about 2.4255 g/cc.
- a glass-ceramic article is formed by controlled crystallization, in situ, of a glass article.
- a batch of glass-forming ingredients containing a nucleating or crystallization-promoting agent is initially melted to form a homogeneous liquid which is then simultaneously cooled and shaped to form a glass article of desired dimensions and configuration.
- the thus formed glass article is subsequently heat treated in accordance with a defined time-temperature schedule to develop nuclei in the glass which act as sights for the growth of crystals as heat treatment proceeds.
- the structure of the resulting glass-ceramic articles comprises relatively uniformly-size crystals homogeneously dispersed in a residual glassy matrix, which crystalline phase constitutes the predominant proportion of the article.
- conventional practices comprise selecting a glass-ceramic material with a high crystalline phase, i.e., above 75% by volume, for high strength.
- a glass-ceramic material with a high crystalline phase i.e., above 75% by volume
- the height of a laser formed protrusion extending above a glass -ceramic substrate increases as the amount of crystalline phase in the glass-ceramic substrate increases.
- the protrusion height sensitivity to laser pulse energy also increases as the amount of crystalline phase in the glass-ceramic substrate increases.
- the protrusion height sensitivity to pulse energy and protrusion height itself are controlled by controlling the amount of crystalline phase in the glass-ceramic substrate.
- a conventional glass formulation is prepared and cast into a substrate of a desired shape and dimensions.
- the heat treatment to effect nucleation and growth of a crystalline phase is controlled, as by controlling time and temperature, so that the resulting glass-ceramic substrate comprises less than about 70% by volume of crystalline phase, for example, below about 50% by volume, even below 30% by volume.
- the protrusion height and protrusion height sensitivity to pulse energy is reduced by limiting the amount of crystalline phase in a sufficient amount to achieve that objective, while ensuring that a sufficient amount of crystalline phase is retained in situations requiring strength.
- One having ordinary skill in the art given the objectives of the present invention, can easily optimize the time and temperature for heat treating a glass substrate to achieve a desired volume of crystalline phase for a particular application.
- the bump height or protrusion height of laser formed protrusions during laser texturing of a glass-ceramic substrate is controlled to less than about 150 nm, preferably less than about 100 nm, and the sensitivity of the protrusion height to pulse energy decreased, by limiting the amount of crystalline phase to less than about 70% by volume, such as less than about 50% by volume, even less than about 30% by volume.
- the glass-ceramic substrates employed in the present invention have a density less than about 2.44 g/cc, for example, less than about 2.4255 g/cc.
- the inventive method can be employed to accurately form a landing zone with improved tribological performance by virtue of the precisely controlled uniform protrusions having a controlled height extending about the substrate surface.
- Fig. 2 which comprises a C0 2 laser 20 pulsed by RF driver 21.
- Emitted laser light beam 22 passes through variable beam attenuator 23 and beam expander 44. Expanded laser light beam 22 is then focused by lens 25 onto the surface of i rotating substrate 26 which is driven by spindle 27 powered by motor 28. Substrate 26 and spindle 27 are mounted on a linear slide 29.
- a thermopile detector 30 measures the average laser power, which can be easily translated into pulse energy.
- opposite surfaces of .a glass-ceramic substrate can be laser textured in accordance with the present invention.
- the present invention enables accurate control of the height of laser formed protrusions, thereby optimizing tribological and magnetic performance compatible with the escalating requirements for high areal density and mobile computer data storage applications, such as laptop computers.
- conventional glass formulations can be heat treated to form a glass-ceramic substrate having a controlled amount of crystalline phase.
- the substrate is normally initially polished to provide a specular surface and a landing zone accurately formed thereon by laser texturing, leaving a specular data zone with maximized areal recording density.
- the magnetic layers deposited in accordance with the present invention can be any of those conventionally employed in the production of magnetic recording media.
- Such conventional magnetic alloys include, but are not limited to, cobalt (Co) -base alloys, such as cobalt- chromium (CoCr) , cobalt-samarium (CoSm) , cobalt-chromium- tantalum (CoCrTa) , cobalt -nickel -chromium (CoNiCr) , cobalt-chromium-samarium (CoCrSm) , cobalt-chromium- platinum-tantalum (CoCrPtTa) , cobalt-chromium-platinum (CoCrPt) , cobalt-nickel-platinum (CoNiPt) , cobalt-nickel- chromium-platinum (CoNiCrPt) and cobalt-chromium- platinum-boron (CoCrP
- an underlayer can be deposited on the textured substrate prior to depositing the magnetic layer.
- the underlayer can comprise chromium or a chromium-alloy, such as chromium-vanadium or chromium-titanium, oxygen-doped chromium, tungsten or a tungsten alloy.
- a protective overcoat such as a carbon overcoat
- a lubricant topcoat deposited on the protective overcoat.
- the underlayer, magnetic layers and protective overcoat can be applied in a conventional manner, by any of various sputtering techniques, deposited in conventional thicknesses employed in production of magnetic recording media.
- a magnetic recording medium in accordance with the present invention is illustrated in Fig. 3 and comprises a glass-ceramic substrate 30 having a controlled amount of crystalline phase below about 70% by volume.
- An optional seed layer 31 is sputter deposited thereon for controlling the crystallographic orientation of the subsequently deposited layers.
- Underlayer 32, magnetic layer 33 and protective overcoat 34 are sequentially deposited on substrate 30 or optional seed layer 31.
- Fig. 4 the protrusion height vs. pulse energy for glass-ceramic A and B are shown.
- the threshold energy for glass-ceramic B to form laser bumps is greater than that of glass-ceramic A due to its higher transition temperature.
- the protrusion height increases more sharply and exhibits a linear relationship with pulse energy, which may reflect the fact that the density difference between the glass-ceramic phase and glass phase is significantly greater for glass-ceramic B. It is noted, however, that the protrusion shape remains dome-like for glass-ceramic B without noticeable top flattening or collapsing as in the case for glass-ceramic A.
- Fig. 5 depicts the bump diameter and pulse energy relationship for both glass-ceramic A and glass-ceramic B. Again, apparently due to the lower transition temperature, the bump diameter of glass-ceramic A is substantially larger than that of glass-ceramic B, even though the bump height is lower in most cases.
- the operative mechanism enabling reduction of the laser formed protrusion height sensitivity of protrusion height to pulse energy by controlling the amount of crystalline phase is not known with certainty. However, it is believed that the reduction in the amount of crystalline phase results in a lower transition 12 temperature and, hence, pulse energy required to form specific bump height and, hence, lower the sensitivity of bump height to power variation.
- the present invention can be employed to produce any of various types of magnetic recording media including thin film disks, with an attendant improvement in flying stability, glide performance and head-medium interface reliability. Moreover, the precise manner in which a landing zone is laser textured enables increased areal recording density, e.g., an increase of 40% or more, and a reduction in the size of head sliders. In practicing the present invention, one having ordinary skill in the art can easily optimize the annealing regimen in terms of time and temperature in order to achieve a desired degree of crystalline phase consistent with the objectives of the present invention.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP50436499A JP3949732B2 (en) | 1997-06-23 | 1997-07-15 | Controlled laser texturing of glass-ceramic substrates for magnetic recording media |
GB9928808A GB2341177B (en) | 1997-06-23 | 1997-07-15 | Controlled laser texturing glass-ceramic substrates for magnetic recording media |
DE19782279T DE19782279T1 (en) | 1997-06-23 | 1997-07-15 | Controlled laser texturing of glass ceramic substrates for magnetic recording media |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/880,368 US5853820A (en) | 1997-06-23 | 1997-06-23 | Controlled laser texturing glass-ceramic substrates for magnetic recording media |
US08/880,368 | 1997-06-23 |
Publications (1)
Publication Number | Publication Date |
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WO1998058749A1 true WO1998058749A1 (en) | 1998-12-30 |
Family
ID=25376102
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1997/012198 WO1998058749A1 (en) | 1997-06-23 | 1997-07-15 | Controlled laser texturing glass-ceramic substrates for magnetic recording media |
Country Status (7)
Country | Link |
---|---|
US (2) | US5853820A (en) |
JP (1) | JP3949732B2 (en) |
KR (1) | KR100435923B1 (en) |
CN (1) | CN1071149C (en) |
DE (1) | DE19782279T1 (en) |
GB (1) | GB2341177B (en) |
WO (1) | WO1998058749A1 (en) |
Families Citing this family (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5768076A (en) * | 1993-11-10 | 1998-06-16 | International Business Machines Corporation | Magnetic recording disk having a laser-textured surface |
WO1997042629A1 (en) * | 1996-05-09 | 1997-11-13 | Seagate Technology, Inc. | Magnetic recording medium with laser textured glass or glass-ceramic substrate |
US6020045A (en) * | 1996-06-05 | 2000-02-01 | Seagate Technology, Inc. | Textured magnetic recording medium having a transition zone |
JP3930113B2 (en) * | 1996-08-30 | 2007-06-13 | Hoya株式会社 | Glass substrate for magnetic disk |
US6068891A (en) * | 1997-08-15 | 2000-05-30 | Komag, Inc. | Method for laser texturing a glass ceramic substrate and the resulting substrate |
US6068728A (en) * | 1997-08-28 | 2000-05-30 | Seagate Technology, Inc. | Laser texturing with reverse lens focusing system |
US6663938B1 (en) * | 1997-12-12 | 2003-12-16 | Seagate Technology Llc | Media contact zone with bell-shaped texturing features |
US6093472A (en) * | 1999-06-23 | 2000-07-25 | Seagate Technology, Inc. | Magnetic recording medium with laser textured glass or glass-ceramic substrate |
US6589609B1 (en) | 1999-07-15 | 2003-07-08 | Seagate Technology Llc | Crystal zone texture of glass-ceramic substrates for magnetic recording disks |
US20080032931A1 (en) * | 1999-08-25 | 2008-02-07 | Steward Lance E | Activatable clostridial toxins |
FR2857354B1 (en) * | 2003-07-07 | 2005-09-16 | Centre Nat Rech Scient | VITREOUS COMPOSITION OF VITROCERAMIC TYPE, TRANSPARENT IN THE INFRARED |
CN103936299A (en) * | 2007-07-16 | 2014-07-23 | 康宁股份有限公司 | Method for local reversible glass swelling |
US8319861B2 (en) | 2010-06-04 | 2012-11-27 | Apple Inc. | Compensation for black level changes |
US8228406B2 (en) | 2010-06-04 | 2012-07-24 | Apple Inc. | Adaptive lens shading correction |
US8325248B2 (en) | 2010-06-04 | 2012-12-04 | Apple Inc. | Dual processing of raw image data |
FR3072089B1 (en) * | 2017-10-05 | 2022-03-04 | Eurokera | TEXTURED CERAMIC SHEET |
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1997
- 1997-06-23 US US08/880,368 patent/US5853820A/en not_active Expired - Fee Related
- 1997-07-15 DE DE19782279T patent/DE19782279T1/en not_active Withdrawn
- 1997-07-15 JP JP50436499A patent/JP3949732B2/en not_active Expired - Fee Related
- 1997-07-15 WO PCT/US1997/012198 patent/WO1998058749A1/en active IP Right Grant
- 1997-07-15 GB GB9928808A patent/GB2341177B/en not_active Expired - Fee Related
- 1997-07-15 CN CN97182116A patent/CN1071149C/en not_active Expired - Fee Related
- 1997-07-15 KR KR10-1999-7012197A patent/KR100435923B1/en not_active IP Right Cessation
-
1998
- 1998-11-12 US US09/190,172 patent/US5958545A/en not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5108781A (en) * | 1990-03-12 | 1992-04-28 | Magnetic Peripherals Inc. | Process for manufacturing selectively textured magnetic recording media |
US5595791A (en) * | 1993-11-10 | 1997-01-21 | International Business Machines Corporation | Process for texturing brittle glass disks |
Also Published As
Publication number | Publication date |
---|---|
US5853820A (en) | 1998-12-29 |
JP3949732B2 (en) | 2007-07-25 |
CN1071149C (en) | 2001-09-19 |
JP2002513500A (en) | 2002-05-08 |
CN1268907A (en) | 2000-10-04 |
GB2341177B (en) | 2001-02-14 |
GB9928808D0 (en) | 2000-02-02 |
US5958545A (en) | 1999-09-28 |
DE19782279T1 (en) | 2000-06-15 |
KR100435923B1 (en) | 2004-06-12 |
KR20010014138A (en) | 2001-02-26 |
GB2341177A (en) | 2000-03-08 |
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