WO2010148061A2 - Electrophoretic particles - Google Patents
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- WO2010148061A2 WO2010148061A2 PCT/US2010/038780 US2010038780W WO2010148061A2 WO 2010148061 A2 WO2010148061 A2 WO 2010148061A2 US 2010038780 W US2010038780 W US 2010038780W WO 2010148061 A2 WO2010148061 A2 WO 2010148061A2
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- particles
- electrophoretic medium
- electrophoretic
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- polymer
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/165—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on translational movement of particles in a fluid under the influence of an applied field
- G02F1/166—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on translational movement of particles in a fluid under the influence of an applied field characterised by the electro-optical or magneto-optical effect
- G02F1/167—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on translational movement of particles in a fluid under the influence of an applied field characterised by the electro-optical or magneto-optical effect by electrophoresis
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/44—Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/10—Esters
- C08F220/22—Esters containing halogen
- C08F220/24—Esters containing halogen containing perhaloalkyl radicals
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/10—Esters
- C08F220/12—Esters of monohydric alcohols or phenols
- C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
- C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
- C08F220/1812—C12-(meth)acrylate, e.g. lauryl (meth)acrylate
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/165—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on translational movement of particles in a fluid under the influence of an applied field
- G02F1/1675—Constructional details
- G02F2001/1678—Constructional details characterised by the composition or particle type
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2202/00—Materials and properties
- G02F2202/02—Materials and properties organic material
- G02F2202/022—Materials and properties organic material polymeric
Definitions
- This invention relates to electrophoretic particles (i.e., particles for use in an electrophoretic medium) and processes for the production of such electrophoretic particles.
- This invention also relates to electrophoretic media and displays incorporating such particles. More specifically, this invention relates to electrophoretic particles the surfaces of which are modified with polymers.
- Electrophoretic displays have been the subject of intense research and development for a number of years. Such displays can have attributes of good brightness and contrast, wide viewing angles, state bistability, and low power consumption when compared with liquid crystal displays.
- Electrophoretic particles, fluids and fluid additives see for example U.S. Patents Nos. 5,961,804; 6,017,584; 6,120,588; 6,120,839; 6,262,706; 6,262,833; 6,300,932; 6,323,989; 6,377,387; 6,515,649; 6,538,801; 6,580,545; 6,652,075; 6,693,620; 6,721,083; 6,727,881; 6,822,782; 6,870,661; 7,002,728; 7,038,655; 7,170,670; 7,180,649; 7,230,750; 7,230,751; 7,236,290; 7,247,379; 7,312,916; 7,375,875; 7,411,720; 7,532,388; and 7,679,814; and U.S.
- a single particle medium has only a single type of electrophoretic particle suspending in a colored suspending medium, at least one optical characteristic of which differs from that of the particles.
- a dual particle medium has two different types of particles differing in at least one optical characteristic and a suspending fluid which may be uncolored or colored, but which is typically uncolored.
- Both single and dual particle electrophoretic displays may be capable of intermediate gray states having optical characteristics intermediate the two extreme optical states already described.
- Some of the aforementioned patents and published applications disclose encapsulated electrophoretic media having three or more different types of particles within each capsule. For purposes of the present application, such multi-particle media are regarded as sub-species of dual particle media.
- electrophoretic media are regarded as sub-species of encapsulated electrophoretic media.
- electrophoretic media require the presence of a fluid.
- this fluid is a liquid, but electrophoretic media can be produced using gaseous fluids; see, for example, Kitamura, T., et al, "Electrical toner movement for electronic paper-like display", IDW Japan, 2001, Paper HCSl-I, and Yamaguchi, Y., et al., "Toner display using insulative particles charged triboelectrically", IDW Japan, 2001, Paper AMD4-4). See also U.S. Patents Nos.
- Such gas-based electrophoretic media appear to be susceptible to the same types of problems due to particle settling as liquid-based electrophoretic media, when the media are used in an orientation which permits such settling, for example in a sign where the medium is disposed in a vertical plane.
- particle settling appears to be a more serious problem in gas-based electrophoretic media than in liquid-based ones, since the lower viscosity of gaseous suspending fluids as compared with liquid ones allows more rapid settling of the electrophoretic particles.
- microcell electrophoretic display A related type of electrophoretic display is a so-called "microcell electrophoretic display".
- the charged particles and the fluid are not encapsulated within microcapsules but instead are retained within a plurality of cavities formed within a carrier medium, typically a polymeric film.
- a carrier medium typically a polymeric film.
- this invention provides an electrophoretic medium comprising a plurality of pigment particles in a fluid, the pigment particles having a polymer chemically bonded to the pigment particles, wherein the polymer comprises about 0.1 to about 5 mole per cent of repeating units derived from a fluorinated acrylate or fluorinated methacrylate monomer.
- the electrophoretic medium of the present invention may incorporate any of the optional features of polymer shells described in the aforementioned WO 02/093246.
- the preferred proportion of polymer in the coated particles will typically be substantially as described in the aforementioned WO 02/093246, namely that the particles have from about 4 to about 15, desirably from about 8 to about 12, per cent of the weight of the particles of the polymer bonded to the particles.
- the particles may comprise a metal oxide or hydroxide, for example titania.
- the polymer may comprise charged or chargeable groups, for example amino or carboxylic acid groups.
- the polymer may comprise a main chain and a plurality of side chains extending from the main chain, each of the side chains comprising at least about four carbon atoms.
- the polymer will be formed from two or more acrylate and/or methacrylate monomers.
- the fluorinated monomer will be used in combination with a non- fluorinated acrylate or methacrylate monomer (i.e., the polymer may comprises residues derived from both fluorinated and non-fluorinated acrylate and/or methacrylate monomers), lauryl methacrylate being a preferred monomer for this purpose.
- the molar ratio of fluorinated monomer to non-fluorinated monomer may vary but the fluorinated monomer will typically comprises from about 1 to about 5 mole per cent of the total monomer in the polymer. Highly fluorinated monomers containing at least three fluorine atoms are preferred.
- a specific preferred fluorinated monomer is 2,2,2-trifluoroethyl methacrylate, but other fluorinated monomers may also be used, for example 2,2,3, 4,4,4-hexafluorobutyl acrylate and
- This invention extends to an electrophoretic display comprising an electrophoretic medium of the present invention and at least one electrode arranged to apply an electric field to the electrophoretic medium, and to an electronic book reader, portable computer, tablet computer, cellular telephone, smart card, sign, watch, shelf label or flash drive comprising such a display.
- Figures IA and IB are schematic cross-sections through a first electrophoretic display of the present invention in which the electrophoretic medium comprises a single type of particle in a colored suspending fluid.
- Figures 2A and 2B are schematic cross-sections, generally similar to those of
- FIGS. IA and IB respectively through a second electrophoretic display of the present invention in which the electrophoretic medium comprises two different types of particle, bearing charges of opposite polarity, in an uncolored suspending fluid.
- Figures 3A and 3B are schematic cross-sections, generally similar to those of
- FIGS. 2A and 2B respectively through a third electrophoretic display of the present invention in which the electrophoretic medium comprises two different types of particle, bearing charges of the same polarity but differing in electrophoretic mobility, in an uncolored suspending fluid.
- Figures 4A and 4B illustrate a polymer-dispersed electrophoretic medium of the present invention and the process used to produce this medium.
- Figure 5 is a bar graph showing the variation of zeta potential with proportion of fluorinated monomer in the polymer shell in the experiments reported in Example 1 below.
- Figure 6 is a bar graph showing the variation of dark state and white state instabilities with proportion of fluorinated monomer in the polymer shell in the experiments reported in Example 3 below.
- Figure 7 is a bar graph showing the variation of maximum white state, minimum dark state, and total dynamic range with proportion of fluorinated monomer in the polymer shell in the experiments reported in Example 3 below.
- the electrophoretic medium of the present invention may be of any of the types described in the aforementioned E Ink and MIT patents and applications, and preferred embodiments of such media will now be described with reference to Figures 1 to 4 of the accompanying drawings.
- the first electrophoretic display (generally designed 100) of the invention shown in Figures IA and IB comprises an encapsulated electrophoretic medium (generally designated 102) comprising a plurality of capsules 104 (only one of which is shown in Figures IA and IB), each of which contains a suspending liquid 106 and dispersed therein a plurality of a single type of particle 108, which for purposes of illustration will be assumed to be black.
- the particles 108 are electrophoretically mobile and may be formed of carbon black. In the following description, it will be assumed that the particles 108 are positively charged, although of course negatively charged particles could also be used if desired.
- the display 100 further comprises a common, transparent front electrode 110, which forms a viewing surface through which an observer views the display 100, and a plurality of discrete rear electrodes 112, each of which defines one pixel of the display 100 (only one rear electrode 112 is shown in Figures IA and IB).
- Figures IA and IB show only a single microcapsule forming the pixel defined by rear electrode 112, although in practice a large number (20 or more) microcapsules are normally used for each pixel.
- the rear electrodes 112 are mounted upon a substrate 114.
- the suspending liquid 106 is colored such that the particles 108 lying in the positions shown in Figure IA adjacent the rear electrodes 112 are not visible to an observer viewing the display 100 via the front electrode 110.
- the necessary color in the suspending liquid 106 may be provided by dissolving a dye in the liquid. Since the colored suspending liquid 106 and the particles 108 render the electrophoretic medium 102 opaque, the rear electrodes 112 and the substrate 114 can be transparent or opaque since they are not visible through the opaque electrophoretic medium 102.
- the capsules 104 and the particles 108 can be made in a wide range of sizes. However, in general it is preferred that the thickness of the capsules, measured perpendicular to the electrodes, be in the range of about 15 to 500 ⁇ m, while the particles 108 will typically have diameters in the range of about 0.25 to about 2 ⁇ m.
- Figure IA shows the display 100 with the rear electrode 112 negatively charged and the front electrode 110 positively charged. Under this condition, the positively-charged particles 108 are attracted to the negative rear electrode 112 and thus lie adjacent the rear electrode 112, where they are hidden from an observer viewing the display 100 through the front electrode 110 by the colored liquid 106. Accordingly, the pixel shown in Figure IA displays to the observer the color of the liquid 106, which for purposes of illustration will be assumed to be white. (Although the display 100 is illustrated in Figures IA and IB with the rear electrodes 112 at the bottom, in practice both the front and rear electrodes are typically disposed vertically for maximum visibility of the display 100. In general, the media and displays of the invention described herein do not rely in any way upon gravity to control the movement of the particles; such movement under gravity is in practice far too slow to be useful for controlling particle movement.)
- Figure IB shows the display 100 with the front electrode 110 made negative relative to the rear electrode 112. Since the particles 108 are positively charged, they will be attracted to the negatively-charged front electrode 110, and thus the particles 108 move adjacent the front electrode 110, and the pixel displays the black color of the particles 108.
- the capsules 104 are illustrated as being of substantially prismatic form, having a width (parallel to the planes of the electrodes) significantly greater than their height (perpendicular to these planes). This prismatic shape of the capsules 104 is deliberate.
- the particles 108 would tend to gather in the highest part of the capsule, in a limited area centered directly above the center of the capsule.
- the color seen by the observer would then be essentially the average of this central black area and a white annulus surrounding this central area, where the white liquid 106 would be visible.
- the observer would see a grayish color rather than a pure black, and the contrast between the two extreme optical states of the pixel would be correspondingly limited.
- the particles 108 cover essentially the entire cross-section of the capsule so that no, or at least very little white liquid is visible, and the contrast between the extreme optical states of the capsule is enhanced.
- the reader is referred to the aforementioned U.S. Patent No. 6,067,185, and the corresponding published International Application WO 99/10767.
- microcapsules are normally embedded within a solid binder, but this binder is omitted from Figures 1 to 3 for ease of illustration.
- the second electrophoretic display (generally designed 200) of the invention shown in Figures 2A and 2B comprises an encapsulated electrophoretic medium (generally designated 202) comprising a plurality of capsules 204, each of which contains a suspending liquid 206 and dispersed therein a plurality of positively charged black particles 108 identical discussed to those in the first display 100 discussed above.
- the display 200 further comprises a front electrode 110, rear electrodes 112, and a substrate 114, all of which are identical to the corresponding integers in the first display 100.
- FIG. 33 Typically the liquid 206 is uncolored (i.e., essentially transparent), although some color may be present therein to adjust the optical properties of the various states of the display.
- Figure 2A shows the display 200 with the front electrode 110 positively charged relative to the rear electrode 112 of the illustrated pixel.
- the positively charged particles 108 are held electrostatically adjacent the rear electrode 112, while the negatively charged particles 218 are held electrostatically against the front electrode 110. Accordingly, an observer viewing the display 200 through the front electrode 110 sees a white pixel, since the white particles 218 are visible and hide the black particles 108.
- Figure 2B shows the display 200 with the front electrode 110 negatively charged relative to the rear electrode 112 of the illustrated pixel.
- the positively charged particles 108 are now electrostatically attracted to the negative front electrode 110, while the negatively charged particles 218 are electrostatically attracted to the positive rear electrode 112. Accordingly, the particles 108 move adjacent the front electrode 110, and the pixel displays the black color of the particles 108, which hide the white particles 218.
- the third electrophoretic display (generally designated 300) of the invention shown in Figures 3A and 3B comprises an encapsulated electrophoretic medium (generally designated 302) comprising a plurality of capsules 304.
- the display 300 further comprises a front electrode 110, rear electrodes 112, and a substrate 114, all of which are identical to the corresponding integers in the displays 100 and 200 previously described.
- the display 300 resembles the display 200 described above in that the liquid 306 is uncolored and that white negatively charged particles 218 are suspended therein. However, that the display 300 differs from the display 200 by the presence of red negatively charged particles 320, which have a substantially lower electrophoretic mobility than the white particles 218.
- Figure 3 A shows the display 300 with the front electrode 110 positively charged relative to the rear electrode 112 of the illustrated pixel. Both the negatively charged white particles 218 and the negatively charged red particles 320 are attracted to the front electrode 110, but since the white particles 218 have substantially higher electrophoretic mobility, that they reach the front electrode 110 first (note that the optical state shown in Figure 3 A is normally generated by abruptly reversing the polarity off the electrodes in the optical state shown in Figure 3B, thus forcing both the white particles 218 and the red particles 320 to traverse the thickness of the capsule 304, and thus allowing the greater mobility of the white particles 218 to cause them to reach their positions adjacent the front electrode 110 before the red particles 320).
- the white particles 218 form a continuous layer immediately adjacent the front electrode 110, thereby hiding the red particles 320. Accordingly, an observer viewing the display 300 through the front electrode 110 sees a white pixel, since the white particles 218 are visible and hide the red particles 320.
- Figure 3B shows the display 300 with the front electrode 110 negatively charged relative to the rear electrode 112 of the illustrated pixel. Both the negatively charged white particles 218 and the negatively charged red particles 320 are attracted to the rear electrode 112, but since the white particles have higher electrophoretic mobility, when the optical state shown in Figure 3B is produced by reversing the polarity on the electrodes in the optical state shown in Figure 3 A, the white particles 218 reach the rear electrode 112 more quickly than do the red particles 320, so that the white particles 218 form a continuous layer adjacent the electrode 112, leaving a continuous layer of the red particles 320 facing the front electrode 110.
- FIGS 4A and 4B illustrate a polymer-dispersed electrophoretic medium of the present invention and the process used to produce this medium.
- This polymer-dispersed medium contains non-spherical droplets and is prepared by using a film-forming material which produces a film capable of being shrunk substantially after its formation.
- the preferred discontinuous phase for this purpose is gelatin, although other proteinaceous materials, and possibly cross-linkable polymers may alternatively be employed.
- FIG. 4A shows a layer 410 comprising droplets 412 dispersed in a liquid medium 414 which is in the process of forming a film, this layer 410 having been coated on a substrate 416 (preferably a flexible polymeric film, such as a polyester film) previously provided with a layer 418 of a transparent electrically conductive material, such as indium-tin oxide.
- the liquid material forms a relatively thick layer 410 containing essentially spherical droplets 412; as shown in Figure 4A.
- the layer 410 After the layer 410 has formed a solid continuous phase, the layer is then allowed to dry, preferably at about room temperature (although the layer may be heated if desired) for a period sufficient to dehydrate the gelatin, thus causing substantial reduction in the thickness of the layer and producing the type of structure illustrated in Figure 4B, the dried and shrunken layer being designated 410' in Figure 4B.
- the vertical shrinkage of the layer i.e., the shrinkage perpendicular to the surface of the substrate 416) in effect compresses the original spherical droplets into oblate ellipsoids whose thickness perpendicular to the surface is substantially smaller than their lateral dimensions parallel to the surface.
- the droplets are normally sufficiently closely packed that the lateral edges of adjacent droplets contact each other, so that the final forms of the droplets more closely resemble irregular prisms than oblate ellipsoids.
- more than one layer of droplets may be present in the final medium.
- the medium is of the type shown in Figure 4B in which the droplets are polydisperse (i.e., a wide range of droplet sizes are present)
- the presence of such multiple layers is advantageous in that it reduces the chance that small areas of the substrate will not be covered by any droplet; hence, the multiple layers help to ensure that the electrophoretic medium is completely opaque and that no part of the substrate is visible in a display formed from the medium.
- the degree of deformation of the droplets in the final electrophoretic medium is also affected by the initial size of the droplets, and the relationship between this initial size and the thickness of the final layer of electrophoretic medium.
- the larger the average initial size of the droplets and/or the larger the ratio of this average initial size to the thickness of the final layer the greater is the deformation of the droplets from a spherical shape in the final layer.
- the average initial size of the droplets be from about 25 percent to about 400 percent of the thickness of the final layer. For example, in the experiments previously described, in which the thickness of the final layer was 30 ⁇ m, good results were obtained with an initial average droplet size of 10 to 100 ⁇ m.
- Gelatin forms a film by a sol/gel transformation, but the present invention is not restricted to film-forming materials which form their films by such sol/gel transformation.
- the formation of the film may be accomplished by the polymerization of a monomer or oligomer, by the cross-linking of a polymer or oligomer, by radiation-curing of a polymer or by any other known film-forming process.
- this shrinkage need not accomplished by the same type of dehydration mechanism by which a gelatin film shrinks, but may be accomplished by removal of a solvent, aqueous or nonaqueous, from the film, cross-linking of a polymeric film or any other conventional procedure.
- the droplets desirably comprise at least about 40 per cent, and preferably about 50 to about 80 per cent, by volume of the electrophoretic medium; see U. S. Patent No. 6,866,760. It should be stressed that the droplets used in the polymer-dispersed media of the present invention may have any of the combinations of particles and suspending fluids illustrated in Figures 1 to 3.
- the present invention may be applied to any of the forms of encapsulated electrophoretic media shown in Figures 1 to 4. However, the present invention is not restricted to encapsulated and polymer-dispersed electrophoretic media, and may also be applied to microcell and unencapsulated media.
- the optimum proportion of fluorinated monomer may vary somewhat with the specific fluorinated monomer used (and especially its degree of fluorination), the other monomers employed and other factors, including the other particles present in the electrophoretic medium. In general the optimum proportion of fluorinated monomer appears to be about 1 mole per cent, since this level of fluorinated monomer gives a substantial increase in the magnitude of the zeta potential while avoiding the aforementioned disadvantages associated with higher proportions of fluorinated monomer. [Para 46]
- the polymer-coated particles used in the electrophoretic media of the present invention may be produced by any of the processes described in the aforementioned WO 02/093246.
- the particles on which a polymer coating is to be formed are reacted with a bifunctional reagent having a functional group capable of reacting with, and bonding to, the particle and with a polymerizable group, for example a pendant vinyl or other ethylenically unsaturated group.
- a bifunctional reagent having a functional group capable of reacting with, and bonding to, the particle and with a polymerizable group, for example a pendant vinyl or other ethylenically unsaturated group.
- Example 1 Preparation of white titania pigment containing 2,2,2- trifluoroethyl methacrylate and lauryl methacrylate in the polymer shell
- DuPont R-794 titania, surface functionalized with 3-(trimethoxysilyl)propyl methacrylate was prepared substantially as described in the aforementioned PCEP applications.
- 500 g of this pigment was dispersed in 426 g (500 mL) of toluene by sonication.
- a l L jacketed glass reactor was charged with 1.7158 moles of monomer divided between lauryl methacrylate and TFEM to yield the desired molar concentrations of each monomer.
- the molar proportions of TFEM were 0.1, 1, 5, 10, 25, and 50 mole % with the remainder being lauryl methacrylate.
- the pigment dispersion was added to the reactor, and the reactor was purged with nitrogen and heated to 65°C.
- a free-radical initiator (5.O g of 2,2'-azobis(2-methylpropionitrile, AIBN), previously dissolved in 110 mL of toluene, was added dropwise over 60 minutes.
- the vessel was heated under nitrogen overnight with continuous agitation at 65°C, then exposed to the atmosphere.
- the mixture was then split into four 1 L plastic bottles, and approximately 500 rnL of further toluene was added to each bottle. The bottles were stirred vigorously.
- the pigment was isolated by centrifugation at 3500 rpm for 20 minutes.
- Example 1 and the following procedure.
- An internal phase was prepared by combining the following in a 250 mL plastic bottle:
- a release sheet was coated with a 25 ⁇ m layer custom polyurethane lamination adhesive as described in U.S. Patent No. 7,012,735 doped with 180 ppm of tetrabutylammonium hexafluorophosphate, and cut to a size slightly smaller than the microcapsule/polymer film pieces.
- the two films were laminated to the coating by running them through a hot roll laminator with the top and bottom rollers set at 12O 0 C, and resultant combined film cut to the desired size.
- Electro-optical measurements were take on the single pixel displays prepared in Example 2 using a PR-650 SpectraScan Colorimeter. In these tests, the displays were repeatedly driven to their black and white extreme optical states using 250 millisecond 15 V pulses, then driven to either their black or white extreme optical state. The reflectivity of the optical state was measured about 3 seconds after the final drive pulse (to allow certain transient effects to pass) and then 2 minutes after the final drive pulse, and the two measurements compared to detect any image instability (i.e., lack of bistability in the image).
Abstract
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Priority Applications (4)
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JP2012516230A JP5580891B2 (en) | 2009-06-16 | 2010-06-16 | Electrophoretic particles |
KR1020127001124A KR101367696B1 (en) | 2009-06-16 | 2010-06-16 | Electrophoretic particles |
CN201080036404.6A CN102640043B (en) | 2009-06-16 | 2010-06-16 | electrophoretic particles |
HK12112007.2A HK1171266A1 (en) | 2009-06-16 | 2012-11-22 | Electrophoretic particles |
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US18737009P | 2009-06-16 | 2009-06-16 | |
US61/187,370 | 2009-06-16 |
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WO2010148061A2 true WO2010148061A2 (en) | 2010-12-23 |
WO2010148061A3 WO2010148061A3 (en) | 2011-04-28 |
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KR (1) | KR101367696B1 (en) |
CN (1) | CN102640043B (en) |
HK (1) | HK1171266A1 (en) |
TW (1) | TWI409305B (en) |
WO (1) | WO2010148061A2 (en) |
Cited By (8)
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WO2013170932A1 (en) | 2012-05-14 | 2013-11-21 | Merck Patent Gmbh | Particles for electrophoretic displays |
WO2013170933A1 (en) | 2012-05-14 | 2013-11-21 | Merck Patent Gmbh | Particles for electrophoretic displays |
WO2013170937A1 (en) | 2012-05-14 | 2013-11-21 | Merck Patent Gmbh | Particles for electrophoretic displays |
WO2013170936A1 (en) | 2012-05-14 | 2013-11-21 | Merck Patent Gmbh | Particles for electrophoretic displays |
WO2013170938A1 (en) | 2012-05-14 | 2013-11-21 | Merck Patent Gmbh | Particles for electrophoretic displays |
US8961831B2 (en) | 2011-05-31 | 2015-02-24 | E Ink California, Llc | Silane-containing pigment particles for electrophoretic display |
US9382427B2 (en) | 2011-06-09 | 2016-07-05 | E Ink California, Llc | Silane-containing pigment particles for electrophoretic display |
US9494808B2 (en) | 2012-05-14 | 2016-11-15 | Merck Patent Gmbh | Particles for electrophoretic displays |
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Also Published As
Publication number | Publication date |
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TWI409305B (en) | 2013-09-21 |
JP5580891B2 (en) | 2014-08-27 |
KR20120034201A (en) | 2012-04-10 |
TW201107430A (en) | 2011-03-01 |
JP2012530283A (en) | 2012-11-29 |
CN102640043B (en) | 2014-10-01 |
CN102640043A (en) | 2012-08-15 |
HK1171266A1 (en) | 2013-03-22 |
WO2010148061A3 (en) | 2011-04-28 |
KR101367696B1 (en) | 2014-02-27 |
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