US3627580A - Manufacture of magnetically sensitized webs - Google Patents

Manufacture of magnetically sensitized webs Download PDF

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Publication number
US3627580A
US3627580A US3627580DA US3627580A US 3627580 A US3627580 A US 3627580A US 3627580D A US3627580D A US 3627580DA US 3627580 A US3627580 A US 3627580A
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magnetic
film
web
particles
fields
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Expired - Lifetime
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Harry J Krall
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Eastman Kodak Co
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Eastman Kodak Co
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    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/84Processes or apparatus specially adapted for manufacturing record carriers
    • G11B5/842Coating a support with a liquid magnetic dispersion
    • G11B5/845Coating a support with a liquid magnetic dispersion in a magnetic field

Abstract

The requirement for time-consuming, costly bulk-erasing of the magnetic sound track on motion picture film is eliminated in the disclosed process. As indicated, film is coated with a magnetically sensitized stripe. Prior to the time when the stripe dries, the film is exposed to a strong particle-orienting magnetic field, thereby to improve the recordability of the stripe. Such particle orientation causes the particles to become unidirectionally magnetized, which in combination with coating irregularities increases measurable noise level. To remove such noise, the invention provides that the film be exposed to alternating magnetic fields of gradually decreasing strength, such fields being disposed after the coating dries and before the film is wound. The invention may be practiced in the manufacture of other magnetically sensitized recording webs.

Description

United States Patent Inventor Appl. No.

Filed Patented Assignee MANUFACTURE OF MAGNETICALLY SENSITIZED WEBS 8 Claims, 1 Drawing Fig.

2,784,259 3/1957 Camras 179/1002 FOREIGN PATENTS 933,762 8/1963 Great Britain 117/238 1,116,011 6/1968 Great Britain 117/238 OTHER REFERENCES Spratt, Magnetic Tape Recording, 2- 65, pages 15, 109, 1 12, 1 14 Primary Examiner-William D. Martin Assistant Examiner-B. D. Pianalto Attorneys-Walter O. Hodson and Robert F. Cody ABSTRACT: The requirement for time-consuming, costly bulk-erasing of the magnetic sound track on motion picture [52] U.S.Cl llll77/223385, mm is eliminated in the disclosed process AS indicated mm is 51 I I Cl coated with a magnetically sensitized stripe. Prior to the time i50 i H0117! /080 when the wipe dries, the mm is exposed to a strong panic|e ie 0 re 1 I223 orienting magnetic field thereby to improve the recordability 35 of the stripe. Such particle orientation causes the particles to [56] References cued betclpme tu nidi rectiolnally magnetized, which COITlblllflIlOi] WI coa mg irregu an ies increases measura c noise eve. UNITED STATES PATENTS To remove such noise, the invention provides that the film be 3,1 Bauer l X exposed to alte nating magneic fields of gradually decreasing 3,256,1 12 6/1966 Camras 1 17/238 strength, such fields being disposed after the coating dries and l Fl'ledmal'l before the is wound The invention may be practiced in 34l6'949 12/1968 Camras 117/238 UX the manufacture of other magnetically sensitized recording 3,490,945 1/1970 Slovinsky 117/238 X b PRIOR ART THE INVENTION I8 /4 STOCK COATEI? W/NDUP PATENTED DEB] 41971 A TTORNEYS L H mm H N 1C v'V RN A H MANUFACTURE OF MAGNETICALLY SENSITIZED WEBS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to manufacturing processes; and in particular to the manufacture of magnetic recording webs; and still more particularly to the manufacture of motion picture film having a magnetic recording medium thereon.

2. Description of the Prior Art U.S. Pats. No. 2,784,259 and 3,222,205 are representative of art relevant to the invention.

Prior to the invention, motion picture film with a magnetic recording stripe and been manufactured as follows: A web of photographically sensitized film was conveyed from a roll thereof to a windup stage under controlled lighting conditions. As the webs moved along, a hopper deposited a solution, containing a dispersion of elongated magnetic particles, along one edge of the film. Before the solution became dry, the web was passed through a strong magnetic field, parallel to the length of the web, to cause the magnetic particles to orient so that their respective easy directions of magnetization, i.e. their respective major axes, were parallel to the length of the web. This was done so that audio recording on the stripe would be at high resultant" signal levels. The strong magnetic field, while accomplishing its intended purpose of particle orientation, undesirably left such particles so magnetically ordered that the net external field of the stripe was at a constant saturated level everywhere except in the vicinity of stripe discontinuities; and so, because of such discontinuities, and other irregularities within the coating, polarized particle concentrations produce transient output noise signals. Such noise signals have been defined as modulation noise by Skipwith W. Athey, in his treatise (available from the Superintendent of Documents) on Magnetic Tape Recording, SP-5038, pages I60 through 163, prepared under Contract NASw-945, Jan. 1966, National Aeronautics and Space Administration. Obviously, such noise had to be removed "prior to exposure" of the striped film so that high quality visual and audio reproductions would obtain. To this end, so-called bulk-erasure of noise was employed.

With bulk-erasure, spools of film are placed on a rotating table and gradually exposed to a magnetic field of decreasing strength, thus randomizing the distribution of those particle fields which are oriented one way, or the other. A random distribution of particle orientations produces a minimum net field in the vicinity of a sound-reproducing head: which is to say that such a distribution produces a minimum detectable noise.

Bulk-erasure is effective for its intended purpose, but adds a time-consuming, separate and expensive, step to the manufacturing process in question.

As used throughout the specification, all references to noise" are to be taken as references to modulation noise. (noise which is of an AC nature, and which is dependent on the number and arrangement of particles in a magnetic coating, is also referred to by Athey, but use of the invention will have virtually no effect on removal ofAC noise.

SUMMARY OF THE INVENTION Before indicating the nature of the invention, it is considered instructive to indicate first what the invention is not: the invention has nothing to do with the erasure of purposely recorded intelligence on a magnetic recording medium. Rather, the invention is concerned with supplying" spools of magnetically sensitized web material to users thereof, which spools need not be erased-to remove recorded manufacturing noise-prior to recording thereon. Supplying noise-free magnetically sensitized webs is especially critical in the case of motion picture film for the obvious reason that taking motion pictures, with accompanying audio, is a once-through-thecamera procedure. That is, magneticsound cameras and magnetic-sound printers are customarily built without erase heads,

and their perfonnance is limited by the noise level of the film as supplied by the manufacturer.

The invention suggests, in the manufacture of magnetically sensitized webs, the in-line" use of alternating magnetic fields, which alternating fields are disposed in the direction of web travel after the stripe of oriented particles dries, but before the windup part of the process. The alternating fields gradually decrease in strength from drier to windup; and the maximum field strength so employed is preferably at least that necessary to reverse the direction of saturation of the particles. Movement of the web through gradually decreasing alternating fields causes the respective field orientations of the individual particles, one way or the other, to be in accordance with a noiseless" statistical distribution, and this is so even through the axes of the particles are all disposed one way for purposes of improved recordability.

An object of the invention is to provide an improved process for manufacturing magnetically sensitized recording webs.

Another object of the invention is to provide an improved process for manufacturing magnetic-recording webs devoid of manufacturing noise.

Another object of the invention is to provide a method of manufacturing motion picture film having a magnetically sensitized recording medium thereon, which method obviates the prior need for bulk-erasure of manufacturing noise from the film.

The invention will be described with reference to the FIGURE. The FIGURE shows the prior art method of manufacturing magnetically sensitized webs as improved by the invention.

With reference to the FIGURE, a photographically sensitized web 10 of motion picture film is continuous from a roll 12 thereof to a windup section 14. Magnetic particles, dispersed throughout a coating solution 16, are applied to the web 10 at a coating stage 18, say by means of a hopper. The coating solution 16, as indicated by the cross section A, has the axes (and fields) of its magnetic particles oriented in all directions. The orientation (and field) of a particle is shown by a small arrow, circled dots and circled crosses indicating, respectively, arrows out of and into the figure. The coating solution, as represented in cross section A, has the following irregularities: a depression 20, a mound 22, a bubble 24 and a cluster 25 of particles, all of which irregularities may inadvertently occur during application of the coating 16 to the web 10. A magnetic pickup head disposed proximate the coating of the cross section A would see no resultant (noise) field at the depression 20; at the mound 22; at the bubble 24, or at the particle cluster 25.

While a web with a cross section A is virtually devoid of recorded noise, the recording of intelligence on such a web leaves much to be desired. This is because deliberately recorder intelligence is reduced in intensity and quality by those particle fields which are not oriented in accordance with the recorded intelligence.

To improve the recordability of the coating 16, the coated web 10 is passed through the core of a strong solenoid 26 before such coating dries (dryer 28). The solenoid 26 exerts a magnetic field on the particles within the coating 16, causing such particles to orient so that their respective axes are all aligned parallel to the length of the web 10. See cross section B. Recording on a web with its particle axes parallel to the length of the web allows the individual particle fields to switch one way, or the other, in bunches according to the sound being recorded, i.e. at high signal levels. Such increase in recordability creates a noise problem within the web 10: The concentrations of magnetic particles at the dispersion 20 of cross section B, at the bubble 24', at the mound 22, and at the particle cluster 25', appear at noise modulation frequencies; and since the particles of each such concentration are similarly oriented, they produce resultant noise signals which may be picked up by a sound reproducing head. See the signal B associated with the cross section B; the diagram B shows noise signals corresponding to the concentrations of particles.

Were it not for the invention, the web 10 of magnetically sensitized film would be spooled directly by the windup 14; after which the spooled film would have to be bulk-erased, as noted above, so it could be supplied noise-free to users thereof. To avoid this costly and time consuming manufacturing procedure, the invention suggests that decreasing altemating fields be disposed between the dryer 28 and windup section 14 of the process. As presently practiced, at least ten field reversals are provided by an array of equal-strength bar magnets, 30a through k, which magnets are progressively positioned father and farther from the web 10. The magnets are preferably disposed normally to the web 10; and the magnets are so positioned with respect to the web 10 that their respective effective fields at the web decrease progressively in increments of about percent. The effective strength of the magnet 30a at the web is about that necessary to switch the orientations of the fields of the magnetically saturated particles. Thus, the magnet 30a will tend to switch the fields of most particles; the magnet 30b will switch fewer fields, the magnet 300 still fewer, etc. Attendantly a randomized orientation, one way or the other, of particle fields obtains, there being no net resultant noise field within the coating which can be pickup up by a sound reproducing head. The cross section C of the figure shows the axes of all particle similarly oriented, their respective fields being statistically distributed, one way or the other, regardless of the coating irregularities 22", 24", 25". After being wound into spools, the film may be used without further processing.

The invention has been described in detail with particular reference to a preferred embodiment thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. For example, whereas the figure shows equally strong magnets disposed farther and farther from the web 10, the same effect would obtain with progressively weaker magnets all of which are similarly positioned relative to the web; or by differently orienting the magnets. Also, whereas pennanent magnets a through k are preferably employed because they do not themselves generated any heat, electromagnets may be substituted for such magnets; etc.

lclaim:

l. in a process for the manufacture of a web having magnetic recording medium thereon which has a low modulation noise level, which process includes the steps of a, conveying said web from a first point to a windup point,

b. applying a fluid coating of magnetic particles to said web between said first and said windup points,

c. exposing said web to a first magnetic field, after application of said coating and before such coating dries, said field being sufficient to orient similarly the axes of the said particles,

d. drying the said oriented coating, and

e. winding the coated web into a roll thereof at said windup point, the improvement of exposing said web after said coating dries and before said windup point, to alternating magnetic fields of decreasing strength, whereby to randomize one way of the other the orientations of the respective fields of the particles.

2. The process of claim 1 wherein the magnetic particles are generally elongated, and wherein the first magnetic field is disposed to orient the lengthwise axes of the said magnetic particles substantially parallel to the length of the web.

3. The process of claim 1 wherein at least one of the alternating fields is of a strength sufficient to reverse the directions of the fields of the respective particles within the said coating.

4. The process of claim 3 wherein the said alternating fields are provided by an array of permanent magnets.

5. The process of claim 4 wherein the said permanent magnets are bar magnets disposed normally to the said web.

6. A process for the manufacture of motion picture film having a magnetic recording stripe thereon comprising the steps of a. conveying a web of photographically sensitized film from a source thereof to a windup section 4 b. striping a fluid coating of magnetically sensitized material on said film before said film reaches the windup section,

c. passing said film through a unidirectional magnetic field after it is striped and before such stripe dries,

d. exposing said film to alternating magnetic fields of decreasing strength after said stripe dries and before said film is wound, thereby to reduce the modulation noise level of said magnetically striped film, and

e. winding said magnetically striped film into a roll thereof.

7. The process of claim 6 wherein the said fluid contains elongated magnetic particles, wherein the alternating magnetic fields are provided by an array of permanent magnets, and wherein at least one of the alternating fields is strong enough to switch the magnetization of the particles within the stripe.

8. The process of claim 7 wherein the permanent magnets are bar magnets disposed normally to the film,

i I6 i

Claims (7)

  1. 2. The process of claim 1 wherein the magnetic particles are generally elongated, and wherein the first magnetic field is disposed to orient the lengthwise axes of the said magnetic particles substantially parallel to the length of the web.
  2. 3. The process of claim 1 wherein at least one of the alternating fields is of a strength sufficient to reverse the directions of the fields of the respective particles within the said coating.
  3. 4. The process of claim 3 wherein the said alternating fields are provided by an array of permanent magnets.
  4. 5. The process of claim 4 wherein the said permanent magnets are bar magnets disposed normally to the said web.
  5. 6. A process for the manufacture of motion picture film having a magnetic recording stripe thereon comprising the steps of a. conveying a web of photographically sensitized film from a source thereof to a windup section, b. striping a fluid coating of magnetically sensitized material on said film before said film reaches the windup section, c. passing said film through a unidirectional magnetic field after it is striped and before such stripe dries, d. exposing said film to alternating magnetic fields of decreasing strength after said stripe dries and before said film is wound, thereby to reduce the modulation noise level of said magnetically striped film, and e. winding said magnetically striped film into a roll thereof.
  6. 7. The process of claim 6 wherein the said fluid contains elongated magnetic particles, wherein the alternating magnetic fields are provided by an array of permanent magnets, and wherein at least one of the alternating fields is strong enough to switch the magnetization of the particles within the stripe.
  7. 8. The process of claim 7 wherein the permanent magnets are bar magnets disposed normally to the film.
US3627580A 1969-02-24 1969-02-24 Manufacture of magnetically sensitized webs Expired - Lifetime US3627580A (en)

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Cited By (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3953656A (en) * 1973-03-20 1976-04-27 Tdk Electronic Company Magnetic recording medium and preparation thereof
EP0005845A1 (en) * 1978-06-05 1979-12-12 International Business Machines Corporation Method and apparatus for manufacturing magnetic media
US4281043A (en) * 1973-10-31 1981-07-28 Graham Magnetics, Inc. Polymodal magnetic recording media and compositions useful therein
US4451535A (en) * 1980-07-16 1984-05-29 Eastman Kodak Company Magnetic recording elements, process for making the same and their use in recording
US4518626A (en) * 1982-12-29 1985-05-21 Fuji Photo Film Co., Ltd. Process for preparing magnetic recording medium
US4544574A (en) * 1982-11-29 1985-10-01 Fuji Xerox Co., Ltd. Method of manufacturing a magnetic recording medium
US4578280A (en) * 1983-03-08 1986-03-25 Agfa-Gevaert Aktiengesellschaft Process for the production of a magnetic recording material with perpendicular orientation
US4931309A (en) * 1988-01-18 1990-06-05 Fuji Photo Film Co., Ltd. Method and apparatus for producing magnetic recording medium
US5420742A (en) * 1993-07-30 1995-05-30 Minnesota Mining And Manufacturing Degausser for tape with plural recorded segments
US20040051297A1 (en) * 2002-07-15 2004-03-18 Flex Products, Inc., A Jds Uniphase Company Method and apparatus for orienting magnetic flakes
US20040151827A1 (en) * 2002-09-13 2004-08-05 Flex Products, Inc., A Jds Uniphase Company Opaque flake for covert security applications
US20050037192A1 (en) * 2003-08-14 2005-02-17 Flex Prodcuts, Inc., A Jds Uniphase Company Flake for covert security applications
US20050106367A1 (en) * 2002-07-15 2005-05-19 Jds Uniphase Corporation Method and apparatus for orienting magnetic flakes
US20050123755A1 (en) * 2002-09-13 2005-06-09 Flex Products Inc. Alignable diffractive pigment flakes
US20060097515A1 (en) * 2002-07-15 2006-05-11 Jds Uniphase Corporation Kinematic images formed by orienting alignable flakes
JP2008310932A (en) * 2007-06-18 2008-12-25 Hitachi Maxell Ltd Demagnetizing device and demagnetizing method of magnetic recording medium
US7550197B2 (en) 2003-08-14 2009-06-23 Jds Uniphase Corporation Non-toxic flakes for authentication of pharmaceutical articles
US7625632B2 (en) 2002-07-15 2009-12-01 Jds Uniphase Corporation Alignable diffractive pigment flakes and method and apparatus for alignment and images formed therefrom
US7645510B2 (en) 2002-09-13 2010-01-12 Jds Uniphase Corporation Provision of frames or borders around opaque flakes for covert security applications
US7667895B2 (en) 1999-07-08 2010-02-23 Jds Uniphase Corporation Patterned structures with optically variable effects
US7674501B2 (en) 2002-09-13 2010-03-09 Jds Uniphase Corporation Two-step method of coating an article for security printing by application of electric or magnetic field
US7729026B2 (en) 2002-09-13 2010-06-01 Jds Uniphase Corporation Security device with metameric features using diffractive pigment flakes
US7876481B2 (en) 1999-07-08 2011-01-25 Jds Uniphase Corporation Patterned optical structures with enhanced security feature
US7934451B2 (en) 2002-07-15 2011-05-03 Jds Uniphase Corporation Apparatus for orienting magnetic flakes
US8025952B2 (en) 2002-09-13 2011-09-27 Jds Uniphase Corporation Printed magnetic ink overt security image
US8118963B2 (en) 2002-09-13 2012-02-21 Alberto Argoitia Stamping a coating of cured field aligned special effect flakes and image formed thereby
US8343615B2 (en) 2002-07-15 2013-01-01 Jds Uniphase Corporation Dynamic appearance-changing optical devices (DACOD) printed in a shaped magnetic field including printable fresnel structures
US8658280B2 (en) 2002-09-13 2014-02-25 Jds Uniphase Corporation Taggent flakes for covert security applications having a selected shape
US9102195B2 (en) 2012-01-12 2015-08-11 Jds Uniphase Corporation Article with curved patterns formed of aligned pigment flakes
USRE45762E1 (en) 2002-09-13 2015-10-20 Jds Uniphase Corporation Printed magnetic ink overt security image
US9164575B2 (en) 2002-09-13 2015-10-20 Jds Uniphase Corporation Provision of frames or borders around pigment flakes for covert security applications
US9458324B2 (en) 2002-09-13 2016-10-04 Viava Solutions Inc. Flakes with undulate borders and method of forming thereof

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JPH0156452B2 (en) * 1980-02-19 1989-11-30 Sony Corp
JPS613007B2 (en) * 1980-02-22 1986-01-29 Sony Corp
DE3736024C1 (en) * 1987-10-24 1989-03-23 Agfa Gevaert Ag Demagnetising device

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2784259A (en) * 1952-12-17 1957-03-05 Armour Res Found Recording and erase head for magnetic recorders
GB933762A (en) * 1958-12-04 1963-08-14 Emi Ltd Improvements in or relating to magnetic recording media
US3150995A (en) * 1961-04-28 1964-09-29 Rca Corp Magnetic recording element having diisocyanate-based elastomer binder and method forpreparing same
US3256112A (en) * 1962-07-23 1966-06-14 Iit Res Inst Method and apparatus for orienting magnetic particles of a recording medium and magnetic recording medium
GB1116011A (en) * 1965-07-23 1968-06-06 Lew William Karalus Recording tape
US3413141A (en) * 1965-09-02 1968-11-26 Ibm Method and apparatus for making oriented magnetic recording media
US3416949A (en) * 1965-08-02 1968-12-17 Iit Res Inst Low noise record medium and method for producing the same
US3490945A (en) * 1966-11-15 1970-01-20 Rca Corp Magnetic recording element and method for preparing same

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2784259A (en) * 1952-12-17 1957-03-05 Armour Res Found Recording and erase head for magnetic recorders
GB933762A (en) * 1958-12-04 1963-08-14 Emi Ltd Improvements in or relating to magnetic recording media
US3150995A (en) * 1961-04-28 1964-09-29 Rca Corp Magnetic recording element having diisocyanate-based elastomer binder and method forpreparing same
US3256112A (en) * 1962-07-23 1966-06-14 Iit Res Inst Method and apparatus for orienting magnetic particles of a recording medium and magnetic recording medium
GB1116011A (en) * 1965-07-23 1968-06-06 Lew William Karalus Recording tape
US3416949A (en) * 1965-08-02 1968-12-17 Iit Res Inst Low noise record medium and method for producing the same
US3413141A (en) * 1965-09-02 1968-11-26 Ibm Method and apparatus for making oriented magnetic recording media
US3490945A (en) * 1966-11-15 1970-01-20 Rca Corp Magnetic recording element and method for preparing same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Spratt, Magnetic Tape Recording, 2 65, pages 15, 109, 112, 114 *

Cited By (47)

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Publication number Priority date Publication date Assignee Title
US3953656A (en) * 1973-03-20 1976-04-27 Tdk Electronic Company Magnetic recording medium and preparation thereof
US4281043A (en) * 1973-10-31 1981-07-28 Graham Magnetics, Inc. Polymodal magnetic recording media and compositions useful therein
EP0005845A1 (en) * 1978-06-05 1979-12-12 International Business Machines Corporation Method and apparatus for manufacturing magnetic media
US4208447A (en) * 1978-06-05 1980-06-17 International Business Machines Corporation Method for disorienting magnetic particles
US4451535A (en) * 1980-07-16 1984-05-29 Eastman Kodak Company Magnetic recording elements, process for making the same and their use in recording
US4544574A (en) * 1982-11-29 1985-10-01 Fuji Xerox Co., Ltd. Method of manufacturing a magnetic recording medium
US4518626A (en) * 1982-12-29 1985-05-21 Fuji Photo Film Co., Ltd. Process for preparing magnetic recording medium
US4578280A (en) * 1983-03-08 1986-03-25 Agfa-Gevaert Aktiengesellschaft Process for the production of a magnetic recording material with perpendicular orientation
US4931309A (en) * 1988-01-18 1990-06-05 Fuji Photo Film Co., Ltd. Method and apparatus for producing magnetic recording medium
US5420742A (en) * 1993-07-30 1995-05-30 Minnesota Mining And Manufacturing Degausser for tape with plural recorded segments
US7880943B2 (en) 1999-07-08 2011-02-01 Jds Uniphase Corporation Patterned optical structures with enhanced security feature
US7667895B2 (en) 1999-07-08 2010-02-23 Jds Uniphase Corporation Patterned structures with optically variable effects
US7876481B2 (en) 1999-07-08 2011-01-25 Jds Uniphase Corporation Patterned optical structures with enhanced security feature
US9257059B2 (en) 2001-07-31 2016-02-09 Viavi Solutions Inc. Dynamic appearance-changing optical devices (DACOD) printed in a shaped magnetic field including printable fresnel structures
US9522402B2 (en) 2002-07-15 2016-12-20 Viavi Solutions Inc. Method and apparatus for orienting magnetic flakes
US20060097515A1 (en) * 2002-07-15 2006-05-11 Jds Uniphase Corporation Kinematic images formed by orienting alignable flakes
US7047883B2 (en) 2002-07-15 2006-05-23 Jds Uniphase Corporation Method and apparatus for orienting magnetic flakes
US8726806B2 (en) 2002-07-15 2014-05-20 Jds Uniphase Corporation Apparatus for orienting magnetic flakes
US7604855B2 (en) 2002-07-15 2009-10-20 Jds Uniphase Corporation Kinematic images formed by orienting alignable flakes
US7934451B2 (en) 2002-07-15 2011-05-03 Jds Uniphase Corporation Apparatus for orienting magnetic flakes
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US20050106367A1 (en) * 2002-07-15 2005-05-19 Jds Uniphase Corporation Method and apparatus for orienting magnetic flakes
US20040051297A1 (en) * 2002-07-15 2004-03-18 Flex Products, Inc., A Jds Uniphase Company Method and apparatus for orienting magnetic flakes
US7625632B2 (en) 2002-07-15 2009-12-01 Jds Uniphase Corporation Alignable diffractive pigment flakes and method and apparatus for alignment and images formed therefrom
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US8343615B2 (en) 2002-07-15 2013-01-01 Jds Uniphase Corporation Dynamic appearance-changing optical devices (DACOD) printed in a shaped magnetic field including printable fresnel structures
US20050123755A1 (en) * 2002-09-13 2005-06-09 Flex Products Inc. Alignable diffractive pigment flakes
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US7729026B2 (en) 2002-09-13 2010-06-01 Jds Uniphase Corporation Security device with metameric features using diffractive pigment flakes
US20040151827A1 (en) * 2002-09-13 2004-08-05 Flex Products, Inc., A Jds Uniphase Company Opaque flake for covert security applications
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US8025952B2 (en) 2002-09-13 2011-09-27 Jds Uniphase Corporation Printed magnetic ink overt security image
US8118963B2 (en) 2002-09-13 2012-02-21 Alberto Argoitia Stamping a coating of cured field aligned special effect flakes and image formed thereby
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US7550197B2 (en) 2003-08-14 2009-06-23 Jds Uniphase Corporation Non-toxic flakes for authentication of pharmaceutical articles
US7258915B2 (en) 2003-08-14 2007-08-21 Jds Uniphase Corporation Flake for covert security applications
JP4684263B2 (en) * 2007-06-18 2011-05-18 日立マクセル株式会社 The method of manufacturing the demagnetizer and degaussing method and the magnetic recording medium of the magnetic recording medium
JP2008310932A (en) * 2007-06-18 2008-12-25 Hitachi Maxell Ltd Demagnetizing device and demagnetizing method of magnetic recording medium
US9102195B2 (en) 2012-01-12 2015-08-11 Jds Uniphase Corporation Article with curved patterns formed of aligned pigment flakes

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Publication number Publication date Type
BE746382A (en) 1970-07-31 grant
GB1291366A (en) 1972-10-04 application
FR2033015A5 (en) 1970-11-27 application
BE746382A1 (en) grant
DE2008325A1 (en) 1970-11-12 application
DE2008325B2 (en) 1973-07-05 application

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