US3673597A - Method and apparatus for recording and/or displaying images utilizing thermomagnetically sensitive microscopic capsules - Google Patents

Method and apparatus for recording and/or displaying images utilizing thermomagnetically sensitive microscopic capsules Download PDF

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US3673597A
US3673597A US25224A US3673597DA US3673597A US 3673597 A US3673597 A US 3673597A US 25224 A US25224 A US 25224A US 3673597D A US3673597D A US 3673597DA US 3673597 A US3673597 A US 3673597A
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magnetic
image
heat
capsules
magnetic particles
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William R Horst
Lowell Schleicher
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NCR Voyix Corp
National Cash Register Co
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NCR Corp
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    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/02—Making microcapsules or microballoons
    • B01J13/025—Applications of microcapsules not provided for in other subclasses

Definitions

  • the heat and magnetic field sensitive medium incorporates a capsular coating wherein the capsules contain magnetic particles suspended in a heat-meltable material, so that, as the material is changed from a solid to a flowable state by heating thereof, the particles with the scope of the heat image have freedom of motion and are rearranged by the magnetic field to a pattern corresponding to that of the original image, whereby the image is reproduced on the medium upon cooling of the heat-meltable material.
  • U.S. Pat. No. 3,472,695 issued Oct. 14, 1969, on the application of Helmut K'ziufer, Erich Burger, and Hans- Peter Huber, shows and describes a method for forming a visible image in a magnetizable ink layer by selectively heating the surface layer and subjecting the layer to an external magnetic force, the permeability of the magnetizable material depending upon the heating of the material in a predetermined pattern, and then forming a permanent reproduction of the pattern.
  • the magnetic image is produced with the help of variations of the permeability as a function of the temperature, in that relatively small heat differences have a reversible effect as a variable magnetic resistance in the magnetizing or de-magnetizing field.
  • a permanent field or an alternating field with decreasing amplitude that is, whether. the increase or decrease of the permeability is used with the changes in temperature
  • the present invention relates to recording and/or display of images and, more particularly, to a method and apparatus for producing and obtaining permanent but erasable images of optical patterns.
  • This invention brings together several technologies which enable the production of a hard copy at low cost but further provide economies by permitting the copy medium to be reused.
  • the invention shows ways and means to convert an original image to an equivalent heat image, to transfer by conduction the heat image to a heat-andmagnetism-sensitive medium, and to produce the final image by subjecting the heated medium to a magnetic field.
  • optical images are projected onto and are admitted into a photoconductive transducer which converts or transforms these images into thermal or heat images.
  • the thermally sensitive medium which includes a coating of capsules thereon, the capsules containing heat-meltable material in which are suspended a plurality of magnetic particles along with a dispersed non-magnetic material in the nature of a light pigment or like colored matter.
  • the microencapsulated magnetic particles are generally set in the capsular non-magnetic material at room temperature, but they have freedom of motion in the material at elevated temperatures, the magnetic particles being of the order of one to ten microns in dimension, so as to employ a multitude of them within the capsule body.
  • the capsule and the capsular coated medium are the subject matter of a separate patent application and will not be shown and described in detail in this application, but will be incorporated by reference in so far as to teach the importance of the capsular construction in relation to the present invention.
  • the capsular coated medium or substrate may be paper, tape, film-like material, or glass, or it may be associated with a surface of any material which is in sheet form, provided that the surface is compatible to accept the capsular coating and that the proper magnetic field may be applied thereto.
  • the capsules may be coated on an endless tape or on a drum or a disc to be used as the subject of a temporary recording operation of write, erase, and write, in which the information is temporarily stored as the supportingmaterial is moving. Suffice it to say that the heat-meltable characteristic of the capsular coated'medium plays an important part in the working of the present method and apparatus.
  • the assembly includes two parallel electrically conductive surfaces separated by a photoconductive material, so that, when an optical image strikes the photoconductive material, an electric current flows from one conductive surface through the photoconductive material to the other conductive surface. This action locally generates heat in the area struck by the light image, and the heat passes through one of the conductive surfaces to the heat or thermal sensitive material for example, capsular coated paper which paper is adjacent one conductive surface.
  • the thermal sensitive material can be pressed against the outside of the conductor-photoconductive-material package, so the material may be in the form of a sheet, a roll, or a tape, and also be accessible to a preferred magnetic field.
  • the photoconductive material is in the form of a plate having the conductors laced or interwoven in a grid pattern, so that, as the optical image strikes the photoconductive material, the circuit is energized, and the resulting heat image raises the temperature of the capsular material to that degree where the magnetic particles are free to move within the capsules and produce a copy of the optical image.
  • the active element consists of a photoconductive layer on which the conductive strips are deposited, alternate strips being connected to one terminal of a power supply and the remaining strips being connected to the other terminal.
  • An optical image striking the photoconductive material causes an electric current to flow from one strip (or more) to adjacent strips in that area illuminated by the image. This again produces heat which reacts with the thermal sensitive material to allow freedom of the magnetic particles within the capsules.
  • the optical image is converted to an equivalent heat image which, in turn, melts the material within the capsule, so that an electromagnet or a moving permanent magnet displaces or moves the magnetic particles in a manner to effect an image on the coated paper.
  • the magnetic particles When the capsular material sets or is allowed to return to its original, or unheated, condition, the magnetic particles also are set, and the image is therein produced for recordingor display. If it is desired to erase the image, the area is subjected to a thermal element which melts the capsular material, and the particles are then free to move into a distorted field with the aid of the magnet.
  • the above-mentioned recording operation makes the system suitable for storage for whatever length of time the data is required to be stored, and, in addition, it permits movement of the stored data from one place to another while the data is in existence. It also provides a delay of the existence of evanescing data such as is commonly used in operations of computers where a factor is required for a short time and then is erased.
  • This data can be recirculated as often as desired, as might be used in multiplication problems and cal culations, until erased and replaced by another factor.
  • the continuing exciting magnetic field for either writing or erasing is not required after the data is fixed, and it is intended to be reused in the fixed condition until an erasure thereof is desired.
  • the principal object of the present invention is to provide a method and apparatus for recording and/or displaying original images by converting these images into heat images for effecting the record or the display.
  • Another object of the present invention is to provide a method for producing reusable copy from original images wherein the method utilizes a meltable material capsular coated medium.
  • An additional object of the present invention is to provide a printing and/or display device with characteristics whereby the printing and/or display may be retained or may be erased for reuse.
  • a further object of the present invention is to provide an information display which is viewable by reflected light and which utilizes both magnetic and non-magnetic particles in the meltable material capsular coating.
  • FIG. 1 is a diagrammatic cross-sectional view of a coated medium responsive to heat and magnetism for producing a record of an original image
  • FIG. 2 is a diagrammatic view of the position of the parts in a negative working medium
  • FIG. 3 is a diagrammatic view of the position of the parts in a positive working medium
  • FIG. 4 is a view of the capsular coating showing the effect of the action of a permanent magnet on the particles within the capsule;
  • FIG. 4a is a view of a modified capsular coating showing the effect of the action of a permanent magnet on the magnetic particles within the capsule;
  • FIG. 5 is a sectional view of a coated medium with the particles displaced and viewable by reflective light in the direction of the arrows;
  • FIG. 6 is a sectional view of a coated medium responsive to heat and magnetism and carried on an endless member for recording and display of printed matter;
  • FIG. 7 is a sectional view of a coated medium responsive to heat and magnetism for producing a display with memory
  • FIG. 8 is a detailed view of the capsule showing a writing condition
  • FIG. 9 is a similar view of the capsule showing an erasing condition.
  • FIG. 10 is a diagrammatic view of the grid pattern portion of a typical transducer.
  • FIG. 1 of the drawings there is shown a recording medium 12 in the form of coated paper which is responsive to heat and to a magnetic field.
  • the structure and the composition of the coated paper are shown and described in a United States patent application of Robert G. Bayless, John .I. Spiwak, Robert W. Brown, and Thurman J. Mattingly Ser. No. 25,223, entitled Articles of Manufacture, which application is co-pending with the instant application, and commonly assigned.
  • the coating on the paper is composed of a plurality of minute capsules or tiny containers with transparent walls, which contain a heat-meltable material suspending tiny magnetic particles therein along with a dispersed non-magnetic light-reflecting material or pigment, the non-magnetic material being of white or other colored pigment; for example, in one composition of the capsule, the pigment is in the form of titanium dioxide.
  • the capsules, containing the magnetic particles suspended in the heat-meltable material can have sizes ranging from about 10 to 200 microns, usually average diameters ranging from about 15 to about microns, and more usually from about 20 to 50 microns.
  • the capsules are composed of a polymeric cell wall material which passes light, the wall enclosing a core containing a mixture of the heat-meltable material and the magnetic particles, and preferably additionally containing the particulate light-reflecting material, which serves to enhance the visual contrast in reflectivity observable upon magnetic alignment of the magnetic particles in a given region within the capsules.
  • the heat-meltable material is a material which does not flow at moderate ambient temperatures yet accommodates movement of the magnetic particles responsive to the magnetic field at slightly elevated temperatures in response to heating. Such a material is usually a solid at the ambient temperature but is changed to a liquid at the elevated temperature to allow the magnetic particles to move freely within the capsules.
  • Suitable materials which fall within this category include the various waxes such as tristearin wax, paraffin wax, beeswax, sperrnaceti wax, camauba wax, hydrocarbon wax, polyethylene wax, silicone wax, grease, vegetable fat, petrolatum, margarine, or the like, which materials have a melting range of from about 60 C. to about 75 C.
  • various waxes such as tristearin wax, paraffin wax, beeswax, sperrnaceti wax, camauba wax, hydrocarbon wax, polyethylene wax, silicone wax, grease, vegetable fat, petrolatum, margarine, or the like, which materials have a melting range of from about 60 C. to about 75 C.
  • the magnetic particles contained within the capsule core can be iron oxides (both red and black), iron flake, nickel flake or powder, stainless steel flake, barium-ferrite, iron carbonyl, or suitable ferro-magnetic alloys. Additionally, it is within the purview of the invention to utilize generally spherical magnetic particles which are themselves capsules in a range of diameter of from about I to about 10 microns and composed of finely divided magnetic pigment, such as red or black iron oxide particles having a particle size ranging from about 0.2 to about 1 micron.
  • the capsular cell wall material can be any of the polymeric materials conventionally employed to form capsules for other purposes, such materials as gelatin-gum arabic, polyvinyl alcohol, starch or the like material which is a water-soluble polymer prior to the formation of the cell wall, yet upon cell wall formation can maintain wall integrity and resistance to breakdown over repeated thermomagnetic cycles to allow reasonable longevity for the magnetic record capsules.
  • the light-reflecting pigment material can be suitable particulate type such as titanium dioxide, zinc oxide, magnesium oxide, zinc sulfide-cadmium sulfide fluorescent pigments, nacreous pigments, aluminum flakes, or red or other colored dyes mixed or in solution with one or more components of the heat-meltable or immobilizing material.
  • dispersing or wetting agents such as oleic acid, sorbitan monooleate, sorbiton trioleate, or the like to assist in uniformly dispersing the particulate light-reflecting material within the immobilizing or heat-meltable material at the time of encapsulation.
  • a typical capsule can contain as core material the following components in the indicated concentrations by weight: magnetic particles 5 percent to 35 percent, heat-meltable or immobilizing material 80 percent to 60 percent, particulate lightreflecting material 0 percent to percent, and dispersing or wetting agents 0 percent to 5 percent.
  • the total of the maximum percentages may be seen to be larger than 100 percent; however, the light-reflecting material and a wetting agent are not utilized under certain conditions.
  • FIG. 1 shows the structural elements of the invention in diagrammatic form, wherein a low-intensity image 14 is provided, a source of this image being one generated on the face of a cathode ray tube 15, which image is transferred and focused onto a selected surface.
  • the image can also be obtained from an optical arrangement such as that used in a microform viewer or the like, and the image can be made up of any color or combination of color light, the only restriction being that the receiving surface or device must exhibit a sensitivity to that part of the electromagnetic spectrum.
  • the second element is a receiving surface or device in the nature of an opaque transducer 16, which converts the optical image into a corresponding or equivalent heat image.
  • the transducer is prepared and constructed by depositing a thin layer of gold 18 onto the surface of a glass plate 20, after which a fine interdigital electrode or grid pattern is formed by well known photo-resist methods.
  • a layer 22 of a photoconductive material such as cadmium sulfide or other like material is then deposited over the electrode pattern.
  • the electrodes are connected to a source of electrical energy to provide heat by means of the flow of current across the electrode pattern, the resistance of the gold conductors being sufficiently small so that heat is generated only in the light-struck areas of the activated photoconductive materials.
  • the optical image is projected onto the above-described transducer, the areas where the light falls will become photoconductive, and the flow of the resistive current will produce heat in these selected areas.
  • the amount of the heat produced is a function of the intensity of the light directed at the particular areas, and the optical image is therefore converted into a corresponding or equivalent heat image which is relatively high in temperature as compared to those areas where no light is directed or allowed to project.
  • the electrical current passing through the electrode grid is, in effect, an amplification of the light energy in producing the required heating for the next step in the process of producing a copy of the optical image.
  • the third element of one embodiment of this invention is the recording medium 12, in the form of a coated paper or the like, as mentioned above, which is best termed a reusable copy medium.
  • the coating on the paper generally comprises a plu rality of capsules 24 having magnetic particles 25 and nonmagnetic pigment particles 27 suspended in heat-meltable material 26.
  • the medium is reusable in that a series of optical images may be projected onto and through the transducer, which converts these optical images into heat images which, in turn, melt the material within the capsules 24, so that the magnetic particles 25 are free to move in the heat-meltable material 26 and around and about the pigment particles 27 when subjected to the influence of a permanent magnet or an electromagnet 30.
  • the material in the capsules After passage of the magnet, in one or the other direction as indicated by the arrows in FIG. 1, across the heated areas, the material in the capsules cools sufficiently so that the print or image is set and therefore readily observable.
  • This is shown by the position of the magnetic particles 25 within the three central capsules, wherein the particles are substantially aligned in an image pattern of the optics, when they are displaced by the moving magnet.
  • the movement and grouping into position of the magnetic particles 25 when acted upon by the electromagnet 30 may take different shapes and forms; however, generally the particles will be displaced in a pattern readily observable when viewed from a certain direction.
  • the size of the electromagnet 30 may be sufficiently large to cover an entire sheet of paper or the like, the magnet being fixed rather than movable, and actuated or pulsed in timely manner with the formation of the heat image to effectively displace the particles within the capsules 24. If it is desired to erase or delete the image thus presented, it is only necessary to reheat the entire area of matter on the coated paper. and again subject the area to the action of the magnet. This effectively changes the direction and alignment of the magnetic particles within the capsules, so that they are no longer aligned in a pattern corresponding to the original optical image.
  • the capsular material as described above would be white pigmented, as shown in FIG. 2 at the left side thereof, prior to the above sequence of operations, thus producing a black image on a white background when the magnet 30 is moved across the field of view and, observing in the direction of the arrows, the image being portrayed is represented by the three central capsules.
  • the original state of the coated paper is in its white reflective form, as seen by the position of the pigment particles 27 in the lower portion of the capsules, it is called a negative working medium in that, wherever light was projected in the initial image, a black permanent record is made, as shown by the displacement of the magnetic particles 25 in the lower portion of these three capsules.
  • the final image would be a positive.
  • the recording medium has fixed an initial black form, as shown at the left side in FIG. 3, it would be a positive working system in that, where the light struck the surface of the transducer and was converted for the purpose of heating the corresponding areas of the coated paper, the final image would be white, as observed from the location of the pigment particles 27 within the three central capsules.
  • the optical image was again generated from negative microfilm, the final permanent copy would now also be a negative.
  • This ability of the same recording medium to be either positive or negative working provides great flexibility in producing the choice of hard copy (positive or negative) regardless of the state of the optical information.
  • the position of the magnetic field must of course be different from that of the negative working system, as seen from the position of the magnets in FIGS. 2 and 3.
  • the contents of the capsules 24 are solidified, and the recording medium 12 can be removed from the apparatus and used indefinitely.
  • the entire paper can be heated, and, by subjecting the paper to the magnetic field in proper position,
  • the coating can be reset in either condition (positive or negative working).
  • Information can be recorded on the medium as described and removed from the apparatus for filing, and, at a later date, additional information can be added to the medium in an area not heretofore used without erasing the original data.
  • additional information can be added to the medium in an area not heretofore used without erasing the original data.
  • the magnetic particles 25 in the two capsules or containers located adjacent the pole pieces of the magnet are shown displaced toward the bottom of the capsules, thereby exposing the non-magnetic suspension material 26 when viewed in a direction shown by the arrows.
  • the magnetic material is in the form of ferric oxide, which is dark in color, in the area adjacent the pole pieces the material 26 effectively masks out the dark or black particles to show a white area on a black background.
  • the pigment particles 27 are not shown in FIG. 4, it being known that the heat-meltable suspension material 26 may have characteristics which are similar to those of the pigmented particles. Various shades and colors of the waxes, etc., used for the meltable material are available; however, one of the best results is obtained from a material having a milk-like appearance. Therefore it is not always necessary to include the additional pigment for effective contrast with the magnetic particles.
  • the substrate or paper 12 is coated with the capsules 24, and, by attracting the magnetic particles to one side of the capsule, the characters are displayed in a manner viewable by reflective light, wherein a portion of the paper I2 is coated with capsules and the capsules have been heated and subjected to a magnetic field.
  • the paper is viewed from the direction shown by the arrows, the two capsules at either end will appear black to the eye by reason of reflected light, while the two central capsules will appear white.
  • FIG. 6 there is shown a slightly different aspect of the recording medium, which is carried on an endless belt 40 to provide a reflector-type light display which is capable of displaying a number of lines of data but which is resettable.
  • the converted or displayed information is held permanently without the expenditure of energy beyond that used in establishing the initial information.
  • the important features are that multiple lines of data can be presented to the viewer, that the data is displayed without expenditure of energy such as is required with cathode ray tubes or other type devices, that the information can be changed as desired with energy expended only at the time of change, that the displayed information is viewed by reflected light, which provides for greater acceptability by the user as compared to cathode ray tube devices, and that it is possible to display more than one color.
  • the belt 40 has coated on its outside surface a multitude of the capsules 24 described above and described in detail in the above-referred-to copending U.S. Pat. application.
  • the capsules contain the suspension material 26, the magnetic particles 25, and the non-magnetic dispersal particles 27, it being observed that the material 26 need not be of a meltable type but need only be sufficiently viscous at room temperature and highly fluidic at higher temperatures.
  • the dispersed material (magnetic 25 and non-magnetic 27) is held in place due to the solid nature of the dispersion or suspension material 26, whereas, in the working condition, the suspension material is melted and the particles of dispersed material are free to move about when attracted or displaced by the action of a magnetic field.
  • the capsules are heated to produce a viscous, or fluidic, state, which then permits the magnetic field to provide movement of the black magnetic particles in the desired direction. Once the magnetic particles are positioned properly, the liquid can be caused to solidify or to cool to ambient conditions, and the recorded information will be permanently held until one wishes to change it by repeating the proper sequence of steps.
  • the displayed data is held visible to the eye without the expenditure of additional energy once it has been set in the desired form.
  • the capsules or containers 24 have transparent walls which are not affected by the heating of the material therein, and the size of the capsules can be varied, as mentioned earlier, but the most suitable size is in the range of 20 to 50 microns in diameter, the size depending upon the resolution requirements in the display or recordation of the final image.
  • the meltable material can be viscous at room temperature but should have a significant drop in viscosity upon being heated and should be compatible with the material used for the capsule wall and with the dispersed particles.
  • Mixtures of several capsules of different materials can be prepared, where each of the capsules uses a dispersion material that melts at a different temperature, and it is possible to combine the capsules so mixed and apply them to one belt, so as to thus provide the ability to record different information according to the temperature of the capsular area heated. If different colored non-magnetic pigments are used in the various capsules mixed, a multicolored display is possible where the actual color displayed would be determined by the temperature applied to the system.
  • a heating device in the form of a thermal printer 42 is positioned to input a thermal image on the belt, it being realized that a number of these printer elements can be arranged in a matrix from which any alpha-numeric character can be generated.
  • a properly positioned magnetic field 44 attracts or displaces the black mag netic particles 25 and moves them to the lower side of the capsules on the surface of the belt, where they are held until the temperature is decreased and solidification of the capsule material 26 then fixes the information.
  • the belt 40 moves past the thermal printing elements, multiple lines of data or information are displayed in the form of black characters on a white background.
  • the representation is much simpler than is the actual configuration of the particles.
  • a reset station comprising a heating element 46 and a magnet 48 positioned in relation to each other and to the belt 40 to effectively erase any displayed information.
  • the heating element may be energized in a manner to heat the contents of the capsules across the entire width of the belt, or selected areas may be heated and erased or reset with the magnetic field positioned to act on these areas so that corrections can be made or additional data can be stored in the system.
  • the abovedescribed system produces black characters on a white background; however, it is possible that the elements could have been set in their black-appearing form initially, and thus white characters could be produced on a black background.
  • a thermal printer has been mentioned to produce the heat required to melt the capsular material, other devices, such as heated type or infra-red images projected on the belt could equally serve this purpose.
  • FIG. 7 Another feature of the present invention is shown in FIG. 7 and concerns the provision of an information display which is viewable by reflected light, wherein a transducer 50 converts a projected optical image 52 into a corresponding heat image, which activates a film or layer of capsular coatedsensing material 54, and a magnetic field 56 is applied to the activated sensing material to develop the image.
  • the optical image 52 such as that obtained from a photographic slide projector, is projected onto the transducer element 50, and the transducer,
  • the sensing layer or film 54 consists of a number of the small containers or capsules, each of which holds a mixture of the black magnetic particles 60 and the white non-magnetic particles 62 suspended in the heat-meltable material 58.
  • the incident light will be either reflected or absorbed.
  • the black particles 60 are magnetically displaced toward the front of the cap sules, or to the right in FIG. 7, by the magnet 56, they will absorb the incident light and will appear black to the eye 64.
  • the white material particles 62 are forced to the front, or to the right, and, since these particles reflect the incident light, the image will appear white to the eye 64.
  • the meltable material 58 solidifies, and all the particles 60 and 62 are fixed in the final image state.
  • FIG. 4a there is shown still another example of a suitable sensing layer, which consists of small capsules 24 containing meltable material 26 and needleor plate-like particles 25, where the cross-sectional area of these particles is much greater when the long dimensions of the particles are oriented along a plane perpendicular to incident light rays as compared to their orientation in a direction parallel to the light rays.
  • the perpendicular direction most of the light rays will strike the particles, as seen by the orientation of the magnetic particles in the two capsules between the pole pieces in FIG. 4a, and will be either absorbed or reflected, depending on the characteristics of the particle surface.
  • the parallel direction as seen by the orientation of the magnetic particles in the capsules over the pole pieces in FIG.
  • a further example of a capsular sensing layer is the use of magnetic capsules 70 (FIGS. 8 and 9) having approximately one-half thereof in the nature of an optical absorber and the other half as a reflector, thereby permitting the absor tion or reflection of incident light by proper orientation.
  • the resulting image on the viewing surface may be a positive or a negative reproduction of the input optical image due to the fact that either the white particles 72 or the black particles 74 can be brought into view as soon as the material within the capsules has been melted by the thermal image of the transducer 78.
  • FIG. 8 shows a capsule 70 containing white non-magnetic particles 72 and black magnetic particles 74, wherein incident light at the right side of the capsule is reflected by the location of the white particles.
  • the magnet 76 attracts or displaces the black magnetic particles toward the left side of the capsule upon heating of the meltable material suspending the particles within the capsule.
  • the broom or brush effect of the clustered magnetic particles 74 near the surface of the capsule is readily observable under a sufficiently strong lens.
  • FIG. 9 similarly shows the particles after heating of the material and subjection of the particles to a magnetic field, wherein incident light at the right side of the capsule is absorbed by the location of the black particles.
  • each par-. ticle may include a north pole and a south pole
  • each par-. ticle may include a north pole and a south pole
  • the suspension material is heated and the magnetic action is imposed on the sphere 70, the single magnetic capsule will turn or rotate in response to the magnet.
  • Erasure of the viewing surface in some cases may be accomplished by introducing another optical image; however, for most applications, it is necessary to return the entire area of the sensing material to its original condition prior to re-use of the same areas. This is accomplished by causing the entire surface to be heated and then applying the proper magnetic field (normally the inverse of the field used in the initial cycle).
  • the heating of the entire surface may be performed by uniformly flooding the transducer with light, by the use of a tin oxide layer between the transducer and the sensing material as an electrical heater, or by externally applied heat.
  • the magnetic field required for input and erasure is performed with a permanent magnet or an electromagnet moved across the layer of sensing material at the proper time or by the influence of fixed-position magnets. The preferred choice of methods depends upon such factors as the size of the image area, the desired response time, space limitations, and the need for flexibility in shifting between the functions of input, erase, and positive or negative imaging.
  • the construction of the transducer element depends upon the wavelength of the energy constituting the input optical image and the intensity of the input image.
  • An absorbing layer such as a black pigmented coating applied on or against the input side of the layer of sensing material, serves asthe transducer when the input image is of such intensity that its absorption will produce sufficient heating to activate the sensing layer.
  • An intense laser beam, scanning across the transducer and modulated to produce the image is an example of a form of input suitable for such a transducer, as is an infra-red pattern obtained through a stencil mask.
  • the photoconductive cell transducer of the sur face or interdigital grid type goes through a change in resistance where light strikes the surface and the external power supply causes increased current flow through the photocell, thereby heating those selected areas in the creation of the desired thermal reproduction of the optical input image.
  • the grid pattern of the transducer is shown in FIG. 10, wherein the gold electrodes are connected to an electric source lead 84 and electrodes 82 are connected to a lead 86.
  • the grid is effected by depositing a layer of gold onto the glass plate and etched into the pattern as shown.
  • the gold and cadmium sulfide layered glass plate is most satisfactory; however, other types which are capable of producing sufficient heat, such as semiconductor junction devices arranged as a matrix of photosensitive elements provided by integrated circuit techniques, are equally satisfactory. It is not necessary for the photocell to serve both as light detector and as heat element, as the heat can be provided by a matrix of individual electrical heater elements, each of the heater elements being suitably connected to a corresponding photo-detector of a detector matrix through direct connection or through an amplifier.
  • Phototherrnographic transducers of the above types have been demonstrated capable of producing sufficient heat at input image light levels as low as 4 foot candles. Consequently, transducers of the above type are capable of providing a dis play from input images optically projected from picture projectors, microfilm viewers, television pictures, cathode ray tube computer terminal displays, or any other source of sufficiently intense optical images.
  • the transducer may also consist of a material capable of absorbing the energy of an electron beam and converting this energy to heat.
  • a material capable of absorbing the energy of an electron beam and converting this energy to heat.
  • many materials including conventional cathode ray tube phosphors, become very hot when bombarded by an electron beam. This provides the means for thermally activating the sensing layer when the input image is in the form of an electron beam rather than visible light, and, since an electron beam can provide high electrical current densities, the electric current flowing in the vicinity of the sensing material can provide the magnetic field to orient the particles as well as heat activation.
  • a transducer constructed according to the last-described is capable of giving a reflected light image on a cathode ray tube screen and storing the image indefinitely after the beam is extinguished.
  • Apparatus for producing copy from original images comprising an image source, transducer means receiving the image from the source for converting the original image to an equivalent heat image, said transducer means including a transparent member having a conductive coating thereon responsive to the original image for effecting the formation of said equivalent heat image, a
  • coated medium positioned adjacent the transducer means and responsive to the heat image, said coated medium comprising minute capsules containing meltable material and holding in suspension magnetic particles therein, and
  • the magnetic means disposed to move said particles, upon melting of said material, into a pattern corresponding to that of the original image.
  • the transducer means is an opaque transducer comprising a transparent member having a surface layer of conductive metal thereon, the layer being formed into an electrode pattern for the carrying of current therethrough, means for energizing the conductive metal, and a layer of photoconductive material over the electrode pattern and responsive to the optical image for generating the equivalent heat image from the optical image.
  • the coated medium includes minute capsules on at least one side thereof and having heat-meltable material with pigment particles and magnetic particles suspended therein, the magnetic particles being free to move about and to be substantially aligned upon passage of the magnetic means after the meltable material has been heated to a viscous state, the pigment particles being displaced to a position to form a background for the aligned magnetic particles observable to incident light.
  • a printing and display device comprising an endless member having a coating of minute capsules on at least one side thereof, said capsules containing a heat-meltable material with magnetic particles suspended therein,
  • thermal means positioned adjacent the endless member for heating said material in selected areas of the capsular coating in a printing pattern, said material becoming flowable in nature upon heating thereof, and
  • magnetic means positioned in relation to the thermal means and to the endless member for displacing the magnetic particles within the capsules in a manner for display in the pattern corresponding to the selected areas of the coating after heating of the heat-meltable material within the capsules.
  • reset means comprising a heating element and a magnetic field positioned remote from the thermal and the magnetic means for subsequently heating the coating and for moving the magnetic material within the capsules into a pattern different from the display.
  • thermo means and the magnetic means are so positioned that the capsular magnetic material is substantially aligned in a display pattern observable by reflected light.
  • the device of claim 4 including at least two capsules wherein one capsule contains material meltable at one temperature and the other capsule contains material meltable at a different temperature, the materials being responsive to thermal means to display patterns of different colors.
  • An information display apparatus comprising a projected image, a
  • transducer positioned to receive the projected image and to convert it into an equivalent heat image
  • said layer of sensitive material responsive to the heat image said layer having a plurality of minute capsules containing dark magnetic particles and light non-magnetic particles suspended in a heat-meltable material within the capsules, and
  • magnetic field means arranged to displace the magnetic particles in one direction upon heating of the capsules whereby the magnetic particles form a dark colored display observable by incident light being absorbed by the magnetic particles upon displacement thereof in the melted material
  • said magnetic field means arranged to displace the magnetic particles in another direction upon heating of the capsules whereby the non-magnetic particles form a light colored display observable by incident light being reflected by the non-magnetic particles.
  • said capsules contain magnetic spheres, one portion of each sphere optically absorbing and another portion optically reflecting incident light, whereby subjection of the spheres to the magnetic field displaces the optically reflecting portions in an arrangement to form a positive image.
  • a method ol'producing copy from low-intensity original images comprising the steps of projecting the original image onto a transparent surface, converting the original image into an equivalent heat image by utilizing an opaque transducer comprising a layer of heat generating material and a layer of photoconductive material activated to respond to said original image upon passing of current through the transducer, transferring the heat image onto a medium having a coating thereon, the coating including a plurality of capsules having meltable material with magnetic particles suspended therein, the transfer of the heat image changing the meltable material to a flowable state within the capsules, and
  • a method of producing a printed display observable by reflective means and utilizing a capsular coated medium with meltable material within the capsules and magnetic material suspended in the meltable material comprising the steps of thermally printing a selected pattern onto the medium,
  • thermally printed pattern subjecting the thermally printed pattern to a magnetic field to displace the magnetic material in a display corresponding to the selected pattern.
  • a method of providing an information display viewable observing on the nommagnetic particles the image by reflected light and utilizing a heat and magnetic field sensiplayed by light reflected f the pattern tive medium having a layer of minute capsules containing heat-meltable material with non-magnetic and magnetic particles suspended therein comprising the steps of projecting an original image onto an opaque surface, converting the original image into an equivalent heat image, placing the medium adjacent the image converter so as to equate the heat image with the heat-meltable material 15.
  • the method of claim 14 wherein the heated image is exposed on the other side to a magnetic field to displace the magnetic sensitive portion of the medium into the corresponding pattern to observe the image displayed by light absorbed in the medium.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Thermal Transfer Or Thermal Recording In General (AREA)
  • Electrochromic Elements, Electrophoresis, Or Variable Reflection Or Absorption Elements (AREA)
US25224A 1970-04-02 1970-04-02 Method and apparatus for recording and/or displaying images utilizing thermomagnetically sensitive microscopic capsules Expired - Lifetime US3673597A (en)

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US2522470A 1970-04-02 1970-04-02

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BE (1) BE765096A (cg-RX-API-DMAC10.html)
CA (1) CA943178A (cg-RX-API-DMAC10.html)
CH (1) CH543154A (cg-RX-API-DMAC10.html)
FR (1) FR2092546A5 (cg-RX-API-DMAC10.html)
GB (1) GB1299034A (cg-RX-API-DMAC10.html)
ZA (1) ZA711483B (cg-RX-API-DMAC10.html)

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WO1981002491A1 (fr) * 1980-02-07 1981-09-03 Inst Radiotekhn Elektroniki Ss Procede d'enregistrement sur un support d'une information communiquee sous forme de signaux electriques
AT375780B (de) * 1980-02-29 1984-09-10 Inst Radiotekh Elektron Verfahren zur matrizenaufzeichnung von als elektrische signale uebertragenen informationen aufeinem traeger
US5194881A (en) * 1990-12-07 1993-03-16 Man Roland Druckmaschinen Ag System and method to program a printing form
WO2001002900A1 (en) * 1999-07-05 2001-01-11 Camena Establishment Re-usable information recording medium, and recording method
US20080308537A1 (en) * 2003-10-23 2008-12-18 International Business Machines Corporation Method and apparatus for fast and local anneal of anti-ferromagnetic (af) exchange-biased magnetic stacks

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WO1980000501A1 (fr) * 1978-08-29 1980-03-20 Inst Radiotekh Elektron Porteuse pour enregistrement d'image, methode et dispositif d'enregistrement d'image sur la porteuse

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US3214272A (en) * 1960-05-10 1965-10-26 Method of recording still optical images by means of a photocondugtive layer using thermoplastic imagewise deformation of the image layer
US3221315A (en) * 1962-06-25 1965-11-30 Ncr Co Magnetic recording medium utilizing microscopic capsules containing magnetic material
US3316119A (en) * 1960-09-29 1967-04-25 Litton Systems Inc Recording member for visibly recording radio frequency microwaves
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US3214272A (en) * 1960-05-10 1965-10-26 Method of recording still optical images by means of a photocondugtive layer using thermoplastic imagewise deformation of the image layer
US3316119A (en) * 1960-09-29 1967-04-25 Litton Systems Inc Recording member for visibly recording radio frequency microwaves
US3171106A (en) * 1961-02-27 1965-02-23 Gen Electric Information storage system
US3547628A (en) * 1961-05-01 1970-12-15 Rca Corp Process of thermoplastic deformation imaging
US3196010A (en) * 1962-05-08 1965-07-20 Xerox Corp Electrophotographic process for formation of deformation images in deformable interference films
US3221315A (en) * 1962-06-25 1965-11-30 Ncr Co Magnetic recording medium utilizing microscopic capsules containing magnetic material

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1981002491A1 (fr) * 1980-02-07 1981-09-03 Inst Radiotekhn Elektroniki Ss Procede d'enregistrement sur un support d'une information communiquee sous forme de signaux electriques
US4438443A (en) 1980-02-07 1984-03-20 Institut Radiotekhniki I Elektroniki Akademii Nauk Sssr Method of recording information on a medium in the form of electrical signals
AT375780B (de) * 1980-02-29 1984-09-10 Inst Radiotekh Elektron Verfahren zur matrizenaufzeichnung von als elektrische signale uebertragenen informationen aufeinem traeger
US5194881A (en) * 1990-12-07 1993-03-16 Man Roland Druckmaschinen Ag System and method to program a printing form
WO2001002900A1 (en) * 1999-07-05 2001-01-11 Camena Establishment Re-usable information recording medium, and recording method
US6292460B1 (en) 1999-07-05 2001-09-18 Camena Est Re-usable information recording medium
US20080308537A1 (en) * 2003-10-23 2008-12-18 International Business Machines Corporation Method and apparatus for fast and local anneal of anti-ferromagnetic (af) exchange-biased magnetic stacks
US20100314360A1 (en) * 2003-10-23 2010-12-16 International Business Machines Corporation Method and apparatus for fast and local anneal of anti-ferromagnetic (af) exchange-biased magnetic stacks
US8105445B2 (en) 2003-10-23 2012-01-31 International Business Machines Corporation Method and apparatus for fast and local anneal of anti-ferromagnetic (AF) exchange-biased magnetic stacks
US8470092B2 (en) * 2003-10-23 2013-06-25 International Business Machines Corporation Method and apparatus for fast and local anneal of anti-ferromagnetic (AF) exchange-biased magnetic stacks

Also Published As

Publication number Publication date
CA943178A (en) 1974-03-05
BE765096A (fr) 1971-08-16
FR2092546A5 (cg-RX-API-DMAC10.html) 1972-01-21
GB1299034A (en) 1972-12-06
ZA711483B (en) 1971-11-24
CH543154A (de) 1973-10-15

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