WO2008073719A1 - Procédé de moulage de nervures barrières à l'aide de moules à base de matériaux polymériques hygroscopiques - Google Patents

Procédé de moulage de nervures barrières à l'aide de moules à base de matériaux polymériques hygroscopiques Download PDF

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Publication number
WO2008073719A1
WO2008073719A1 PCT/US2007/085997 US2007085997W WO2008073719A1 WO 2008073719 A1 WO2008073719 A1 WO 2008073719A1 US 2007085997 W US2007085997 W US 2007085997W WO 2008073719 A1 WO2008073719 A1 WO 2008073719A1
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Prior art keywords
mold
relative humidity
temperature
microstructures
typically
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PCT/US2007/085997
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English (en)
Inventor
Akira Yoda
Hiroshi Kikuchi
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3M Innovative Properties Company
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Publication of WO2008073719A1 publication Critical patent/WO2008073719A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/24—Manufacture or joining of vessels, leading-in conductors or bases
    • H01J9/241—Manufacture or joining of vessels, leading-in conductors or bases the vessel being for a flat panel display
    • H01J9/242—Spacers between faceplate and backplate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2211/00—Plasma display panels with alternate current induction of the discharge, e.g. AC-PDPs
    • H01J2211/20—Constructional details
    • H01J2211/34—Vessels, containers or parts thereof, e.g. substrates
    • H01J2211/36—Spacers, barriers, ribs, partitions or the like

Definitions

  • PDPs plasma display panels
  • PLC plasma addressed liquid crystal
  • the barrier ribs separate cells in which an inert gas can be excited by an electric field applied between opposing electrodes.
  • the gas discharge emits ultraviolet (UV) radiation within the cell.
  • UV radiation ultraviolet
  • the interior of the cell is coated with a phosphor that gives off red, green, or blue visible light when excited by UV radiation.
  • the size of the cells determines the size of the picture elements (pixels) in the display.
  • PDPs and PALC displays can be used, for example, as the displays for high definition televisions (HDTV) or other digital electronic display devices.
  • barrier ribs can be formed on glass substrates. This has involved laminating a mold onto a substrate with a glass- or ceramic- forming composition disposed therebetween. Suitable compositions are described for example in U.S. Patent No. 6,352,763. The glass- or ceramic- forming composition is then solidified and the mold is removed. Finally, the barrier ribs are fused or sintered by firing at a temperature of about 550 0 C to about 1600 0 C.
  • the glass- or ceramic-forming composition has micrometer-sized particles of glass frit dispersed in an organic binder. The use of an organic binder allows barrier ribs to be solidified in a green state so that firing fuses the glass particles in position on the substrate.
  • the mold for producing the barrier ribs may be a flexible mold.
  • the flexible mold may comprise a support and a shape-imparting layer comprising the reaction product of at least one (meth)acryl oligomer and at least one (meth)acryl monomer as described in WO2006/113412.
  • the flexible mold may be produced from a transfer mold having substantially the same microstructured pattern as the eventual barrier ribs.
  • US2005/0212182 describes a flexible mold comprising a support containing a moisture to saturation at a temperature and a relative humidity at the time of use by a moisture absorption treatment applied in advanced. As described in paragraph 0031 when the PET film is allowed to sufficiently absorb moisture to stabilize its dimension and is then used to manufacture the mold, dimensional changes of the mold after manufacture can be suppressed.
  • Fig. 1 is a perspective view of an illustrative flexible mold suitable for making barrier ribs.
  • Fig. 2 is a perspective view of an illustrative transfer mold suitable for making the flexible mold of Fig. 1
  • Fig. 3A-3C is a sectional view, in sequence, showing an illustrative method of making a flexible mold from a transfer mold.
  • Fig. 4A-4C is a section view, in sequence of an illustrative method of making a fine structure (e.g. barrier ribs) by use of a flexible mold.
  • a fine structure e.g. barrier ribs
  • the present invention relates to a method of making a flexible mold, the flexible mold, and methods of using the mold to make microstructures.
  • a flexible mold suitable for making microstructures such as barrier ribs.
  • the polymerizable resin and flexible mold can be utilized with other (e.g. microstructured) devices and articles such as for example, electrophoresis plates with capillary channels and lighting applications.
  • Metalacryl refers to functional groups including acrylates, methacrylates, acrylamide, and methacrylamide.
  • Fig. 1 is a partial perspective view showing an illustrative (e.g. flexible) mold 100.
  • the flexible mold 100 generally has a two-layered structure having a planar support layer 110 and a microstructured surface, referred to herein as a shape-imparting layer 120 provided on the support.
  • the flexible mold 100 of Fig. 1 is suitable for producing a grid- like rib pattern (also referred to as a lattice pattern) of barrier ribs on a (e.g. electrode patterned) back panel of a plasma display panel.
  • Another common barrier ribs pattern (not shown) comprises plurality of (non-intersecting) ribs arranged in parallel with each other, also referred to as a linear pattern.
  • the flexible mold will be suitable sized depending on the size of the finished article (e.g. display panel).
  • the flexible mold may be rectangular in shape (700 mm X 400 mm).
  • the depth, pitch, and width of the microstructures of the shape-imparting layer can vary depending on the desired finished article.
  • the depth of the microstructured (e.g. groove) pattern 125 (corresponding to the barrier rib height) is generally at least 100 ⁇ m and typically at least 150 ⁇ m. Further, the depth is typically no greater than 500 ⁇ m and typically less than 300 ⁇ m.
  • the pitch of the microstructured (e.g. groove) pattern may be different in the longitudinal direction in comparison to the transverse direction.
  • the pitch is generally at least 100 ⁇ m and typically at least 200 ⁇ m.
  • the pitch is typically no greater than 600 ⁇ m and preferably less than 400 ⁇ m.
  • the width of the microstructured e.g.
  • the groove) pattern 4 may be different between the upper surface and the lower surface, particularly when the barrier ribs thus formed are tapered.
  • the width is generally at least 10 ⁇ m, and typically at least 50 ⁇ m. Further, the width is typically no greater than 100 ⁇ m and typically less than 80 ⁇ m.
  • the thickness of a representative shape-imparting layer is at least 5 ⁇ m, typically at least 10 ⁇ m, and more typically at least 50 ⁇ m. Further, the thickness of the shape- imparting layer is no greater than 1,000 ⁇ m, typically less than 800 ⁇ m and more typically less than 700 ⁇ m. When the thickness of the shape-imparting layer is below 5 ⁇ m, the desired rib height typically cannot be obtained. When the thickness of the shape- imparting layer is greater than 1,000 ⁇ m, warp and reduction of dimensional accuracy of the mold can result due to excessive shrinkage.
  • the thickness of the polymeric support film is typically at least 0.025 millimeters, and typically at least 0.075 millimeters.
  • the thickness of the polymeric support film is generally less than 0.5 millimeters and typically less than 0.300 millimeters.
  • the tensile strength of the polymeric support film is generally at least about 5 kg/mm 2 and typically at least about 10 kg/mm 2 .
  • the polymeric support film typically has a glass transition temperature (Tg) of about 60 0 C to about 200 0 C.
  • the flexible mold is typically prepared from a transfer mold or master mold, having a corresponding inverse microstructured surface pattern as the flexible mold.
  • a perspective view of an illustrative transfer or master mold 200 suitable for making the flexible mold of Fig. 1 is depicted in Fig. 2.
  • a sectional view of transfer mold 200 of Fig. 2 taken along line IV-IV is depicted in Fig. 3 A.
  • the transfer mold may have a microstructured surface comprised of a cured (e.g. silicone rubber) polymeric material, such as described in Published U.S. Application No. 205/0206034.
  • a master mold e.g. having a metal support layer
  • a polymerizable resin composition 350 is provided at least in the recesses of the microstructured surface of the polymeric transfer or master mold 200. This can be accomplished with known customary coating means such as a knife coater or a bar coater.
  • a support 380 comprising a flexible polymeric film is stacked onto the polymerizable resin filled mold such that the resin contacts the support. While stacked in this manner, the polymerizable resin composition is cured. Photocuring is typically preferred.
  • the support as well as the polymerizable composition are sufficiently optically transparent such that rays of light irradiated for curing can pass through the support.
  • the flexible mold has a haze (as measured according to the test method described in the examples) of less than 15%, typically less than 10% and more typically no greater than 5%.
  • a hygroscopic polymeric support is conditioned and the mold is prepared in a suitable environment having a first temperature and relative humidity.
  • the (i.e. first) temperature and/or relative humidity utilized during the method of making the mold is different than the (i.e. second) temperature and/or relative humidity the mold is subjected to during the method of making the ceramic microstructures.
  • the dimensions (e.g. pitch) of the microstructures of the mold can be adjusted during the mold making process.
  • This aspect is particularly useful when the master mold or transfer mold from which the flexible mold is formed has dimensions (e.g. pitch) that are greater than or less than a target dimension, the target dimension being the dimension of the (e.g.
  • ceramic barrier rib microstructures that are subsequently formed from the flexible mold. If the flexible mold were used to mold a ceramic paste at the same conditions (i.e. temperature and relative humidity) as utilized during the mold making operation, then the microstructure dimensions (e.g. pitch) of the mold are the same at the time it was made in comparison to the time the mold is used to mold the ceramic paste.
  • the first and second temperature are substantially the same (i.e. the difference is not such that the mold dimensions can be adjusted. Accordingly, the first relative humidity differs from the second relative humidity.
  • the (i.e. first) relative humidity of the mold making environment is typically greater than the (i.e. second) temperature and/or relative humidity employed during the method of using the mold to make ceramic microstructures. Accordingly, the microstructures swells such that the pitch of the mold can be reduced to the target dimension during the method of making the mold.
  • the temperature and/or relative humidity of the mold making environment is typically lower to shrink the microstructures thereby increasing the pitch to the target dimensions.
  • the difference in relative humidity between the first and second relative humidity can vary from about 1%RH to as much as about 40%RH.
  • the environment in which the mold is prepared has a (i.e. first temperature and relative humidity) that is the same or relatively close to the temperature and relative humidity employed to precondition the hygroscopic support.
  • the difference is typically no greater than about 10%RH (e.g.
  • the first temperature and relative humidity is also relatively close but not equal to the second temperature and relative humidity. In doing so, the adjustment of the microstructures during the method of making the mold is typically on the order of magnitude of up to about 5 ppm per percent relative humidity.
  • plastic film materials can be used for the support of the flexible mold such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), stretched polypropylene, polycarbonate, and cellulose triacetate. These plastic films may be used either as a single-layered film or as a composite or laminate film of two or more kinds in combination.
  • the surface of the support may be treated to promote adhesion to the polymerizable resin composition.
  • suitable polyester based materials include photograde polyethylene terephthalate and polyethylene terephthalate (PET) having a surface that is formed according to the method described in U.S. Pat. No. 4,340,276.
  • the preconditioning of the hygroscopic support may include applying moisture to the plastic film before being used to make the mold.
  • Suitable means for applying moisture include spraying or immersing the film into (e.g. hot) water, or by passing the film through a high-temperature high-humidity atmosphere such as steam.
  • the plastic film is conditioned in a temperature and humidity controlled chamber to obtain the desired first humidity.
  • Flexible mold 100 can be used to produce (e.g. barrier rib) microstructures on a substrate such as a (e.g. plasma) display panel.
  • the transfer mold and support film Prior to use in the method, the transfer mold and support film are typically conditioned in a humidity and temperature controlled chamber (e.g. 22°C/55% relative humidity) to minimize any dimensional changes thereof.
  • a humidity and temperature controlled chamber e.g. 22°C/55% relative humidity
  • the mold typically has the target dimensions and thus requires no further adjustment such as described in WO 2004/043664.
  • a flat transparent (e.g. glass) substrate 41 having an (e.g. striped) electrode pattern is provided.
  • the flexible mold 100 of the invention is positioned for example by use of a sensor such as a charge coupled device camera, such that the barrier pattern of the mold is aligned with the electrode pattern of the substrate.
  • a barrier rib precursor 45 such as a curable ceramic paste can be provided between the substrate and the shape-imparting layer of the flexible mold in a variety of ways.
  • the curable material can be placed directly in the pattern of the mold followed by placing the mold and material on the substrate, the material can be placed on the substrate followed by pressing the mold against the material on the substrate, or the material can be introduced into a gap between the mold and the substrate as the mold and substrate are brought together by mechanical or other means.
  • a (e.g. rubber) roller 43 may be employed to engage the flexible mold 100 with the barrier rib precursor.
  • the rib precursor 45 spreads between the glass substrate 41 and the shape-imparting surface of the mold 100 filling the groove portions of the mold. In other words, the rib precursor 45 sequentially replaces air of the groove portions. Subsequently, the rib precursor is cured.
  • the rib precursor is preferably cured by radiation exposure to (e.g. UV) light rays through the transparent substrate 41 and/or through the mold 100 as depicted on Fig. 4B. As shown in Fig. 4C, the flexible mold 100 is removed while the resulting cured ribs 45 remain bonded to the substrate 41.
  • radiation exposure to e.g. UV
  • the mold may comprise other (e.g. cured) polymeric materials
  • at least the (e.g. microstructured surface) molding surface of the mold comprises the photopolymerized reaction product of a polymerizable composition generally comprising at least one ethylenically unsaturated oligomer and at least one ethylenically unsaturated diluent.
  • the ethylenically unsaturated diluent is copolymerizable with the ethylenically unsaturated oligomer.
  • the oligomer generally has a weight average molecular weight (Mw) as determined by Gel Permeation Chromatography (described in greater detail in the example) of at least 1,000 g/mole and typically less than 50,000 g/mole.
  • Mw weight average molecular weight
  • the ethylenically unsaturated diluent generally has a Mw of less than 1,000 g/mole and more typically less than 800 g/mole.
  • the oligomer and monomer have functionality that react (e.g. crosslink) upon exposure to light.
  • Representative examples of photopolymerzable groups include epoxy groups, (meth)acrylate groups, olefmic carbon-carbon double bonds, allyloxy groups, alpha-methyl styrene groups, (meth)acrylamide groups, cyanate ester groups, vinyl ethers groups, combinations of these, and the like. Free radically polymerizable groups are preferred. Of these, (meth)acryl functionality is typical and (meth)acrylate functionality more typical. Typically at least one of the ingredients of the polymerizable composition, and most typically the oligomer, comprises at least two (meth)acryl groups.
  • oligomers having (meth)acryl functional groups can be employed.
  • Suitable oligomers include (meth)acrylated urethanes (i.e., urethane (meth)acrylates), (meth)acrylated epoxies (i.e., epoxy (meth)acrylates), (meth)acrylated polyesters (i.e., polyester (meth)acrylates), (meth)acrylated (meth)acrylics, (meth)acrylated polyethers (i.e., polyether (meth)acrylates) and (meth)acrylated polyolefins.
  • the oligomer(s) and monomer(s) preferably have a glass transition temperature (Tg) of about -80 0 C to about 60 0 C, respectively, meaning that the homopolymers thereof have such glass transition temperatures.
  • the oligomer is generally combined with the monomer in amounts of 5 wt-% to 90 wt-% of the total polymerizable composition of the mold.
  • the amount of oligomer is at least 20 wt-%, more typically at least 30 wt-%, and more typically at least 40 wt-%.
  • the amount of oligomer is at least 50 wt-%, 60 wt-%, 70 wt-%, or 80 wt-%.
  • the polymerizable composition of the flexible mold may comprise one or more urethane (meth)acrylate oligomers such as commercially available from Daicel-UCB Co., Ltd. under the trade designation "EB 270" and "EB 8402".
  • the polymerizable composition of the flexible mold may comprise one or more polyolefm (meth)acrylate oligomers such as commercially available from Osaka Organic Chemical Industry Ltd., under the trade designation "SPDBA”.
  • SPDBA polyolefm
  • aromatic (meth)acrylates including phenoxyethylacrylate, phenoxyethyl polyethylene glycol acrylate, nonylphenoxy polyethylene glycol, 3-hydroxyl-3-phenoxypropyl acrylate and (meth)acrylates of ethylene oxide modified bisphenol; hydroxyalkyl (meth)acrylates such as 4-hydroxybutylacrylate; alkylene glycol (meth)acrylates and alkoxy alkylene glycol
  • (meth)acrylates such as methoxy polyethylene glycol monoacrylate and polypropylene glycol diacrylate; polycaprolactone (meth)acrylates; alkyl carbitol (meth)acrylates such as ethylcarbitol acrylate and 2-ethylhexylcarbitol acrylate; as well as various multifunctional (meth)acryl monomers including 2-butyl-2-ethyl-l,3-propanediol diacrylate and trimethylolpropane tri(meth)acrylate.
  • the photocurable rib precursor (also referred to as "slurry” or “paste") comprises at least three components in addition to the photoinitiator just described.
  • the first component is a glass- or ceramic- forming particulate material (e.g. powder). The powder will ultimately be fused or sintered by firing to form microstructures.
  • the second component is a curable organic binder capable of being shaped and subsequently hardened by curing, heating or cooling. The binder allows the slurry to be shaped into rigid or semirigid "green state” microstructures.
  • the binder typically volatilizes during debinding and firing and thus may also be referred to as a "fugitive binder".
  • the third component is a diluent.
  • the diluent typically promotes release from the mold after hardening of the binder material. Alternatively or in additional thereto, the diluent may promote fast and substantially complete burn out of the binder during debinding before firing the ceramic material of the microstructures.
  • the diluent preferably remains a liquid after the binder is hardened so that the diluent phase-separates from the binder material during hardening.
  • the rib precursor composition preferably has a viscosity of less than 20,000 cps and more preferably less than 10,000 cps to uniformly fill all the microstructured groove portions of the flexible mold without entrapping air.
  • the rib precursor composition preferably has a viscosity of between about 20 to 600 Pa-S at a shear rate of 0.1/sec and between 1 to 20 Pa-S at a shear rate of 100/sec.
  • the curable organic binder is curable for example by exposure to radiation or heat.
  • the binder may comprise monomers and oligomers in any combination, so long as the mixture with inorganic particulate material has a suitable viscosity. It is typically preferred that the binder is radiation curable under isothermal conditions (i.e. no change in temperature). This reduces the risk of shifting or expansion due to differential thermal expansion characteristics of the mold and the substrate, so that precise placement and alignment of the mold can be maintained as the rib precursor is hardened.
  • the diluent is not simply a solvent compound for the resin.
  • the diluent is preferably soluble enough to be incorporated into the resin mixture in the uncured state.
  • the diluent should phase separate from the monomers and/or oligomers participating in the cross-linking process.
  • the diluent phase separates to form discrete pockets of liquid material in a continuous matrix of cured resin, with the cured resin binding the particles of the glass frit or ceramic powder of the slurry.
  • the physical integrity of the cured green state microstructures is not greatly compromised even when appreciably high levels of diluent are used (i.e., greater than about a 1 :3 diluent to resin ratio).
  • This provides two advantages. First, by remaining a liquid when the binder is hardened, the diluent reduces the risk of the cured binder material adhering to the mold. Second, by remaining a liquid when the binder is hardened, the diluent phase separates from the binder material, thereby forming an interpenetrating network of small pockets, or droplets, of diluent dispersed throughout the cured binder matrix which facilitates the debinding process.
  • the photocurable rib precursor compositions may comprise a dispersant and/or a thixotropic agent.
  • Each of these additives may be employed in amounts from about 0.05 to 2.0 wt-% of the total rib precursor composition. Typically, the amount of each of these additives is no greater than about 0.5 wt-%.
  • the rib precursor may comprise an adhesion promoter such as a silane coupling agent to promote adhesion to the substrate (e.g. glass panel of PDP).
  • the rib precursor may also optionally comprise various additives including but not limited to surfactants, catalysts, etc. as known in the art.
  • inorganic thixotropes may comprise clays (e.g. bentonite), silica, mica, smectite and others, having particles sizes of less than 0.1 ⁇ m.
  • organic thixotropes may comprise fatty acids, fatty acid amines, hydrogenated castor oil, casin, glue, gelatin, gluten, soybean protein, ammonium alginate, potassium alginate, sodium alginate, gum arabic, guar gum, soybean lecithin, pectin acid, starch, agar, polyacrylic acid ammonium, sodium polyacrylate, ammonium polymethacrylate, potassium salt, (e.g.
  • modified acrylic polymers and copolymers polyhydroxycarboxylic acid amines and amides (such as available from BYK-Chemie Co. under the trade designation "BYK 405"), polyvinyl alcohol, vinyl polymer (vinyl methyl ether/maleic anhydride), vinyl pyrrolidone copolymer, polyacrylamide, fatty acid amide or other aliphatic amide compound, carboxylated methylcellulose, hydroxymethycellulose, hydroxyethylcellulose, xanthic acid cellulose, carboxylated starch, urea urethane, oleic acid, and sodium silicate.
  • the dispersant is a basic polymer, i.e.
  • an acidic polymer may be employed as a dispersant.
  • the rib precursor may comprise 0.1 to 1 parts by weight of a phosphorus-based compound having at least one phosphorus-acid group alone or in combination with 0.1 to 1 parts by weight of a sulfonates based compound. Such compounds are described in
  • the amount of curable organic binder in the rib precursor composition is typically at least 2 wt-%, more typically at least 5 wt-%, and more typically at least 10 wt-%.
  • the amount of diluent in the rib precursor composition is typically at least 2 wt-%, more typically at least 5 wt-%, and more typically at least 10 wt-%.
  • the totality of the organic components is typically at least 10 wt-%, at least 15 wt-%, or at least 20 wt-%. Further, the totality of the organic compounds is typically no greater than 50 wt-%.
  • the amount of inorganic particulate material is typically at least 40 wt-%, at least 50 wt-%, or at least 60 wt-%.
  • the amount of inorganic particulate material is no greater than 95 wt-%.
  • the amount of additive is generally less than 10 wt-%.
  • the paste can be prepared by conventional mixing techniques.
  • the glass- or ceramic- forming particulate material e.g. powder
  • diluent and dispersant at a ratio of about 10 to 15 parts by weight of diluent; followed by the addition of the remainder of the paste ingredients.
  • the paste is typically filtered to 5 microns.
  • the flexible mold can be reused.
  • the number of times the flexible mold can be reused relates to the rib precursor composition employed in the method for making the microstructures.
  • the flexible mold can be reused any number of times ranging from at least one reuse to at least 5 reuses.
  • the polymeric transfer mold can be reused at least 10 times, at least 15 times, at least 20 times, or at least 30 times.
  • the transfer mold can be reused when the extent of swelling of the microstructured surface of the flexible mold is less than 10% and more typically less than 5%, as can be determined by visual inspection with a microscope.
  • the flexible mold is suitable for reuse when the flexible mold is sufficiently transparent.
  • a sufficiently transparent flexible mold typically has a haze (as measured according to the test method described in the examples) of less than 15%, preferably of less than 10% and more preferably no greater than 5% after a single use. Even more preferably, the flexible mold has the haze criteria just described after being reused at least 5 times.
  • the rib precursor comprises a diluent having a solubility parameter that is less than the curable organic binder.
  • the SP can be calculated with the chemical structure (R.F.Fedors, Polym. Eng. ScL, 14(2), p.147, 1974, Polymer Handbook 4 th Edition "Solubility Parameter Values" edited by J.Brandrup, E.H.Immergut and E.A.Grulke).
  • the difference between the solubility parameter of the curable binder and the diluent is at least 1 [MJ/m 3 ] 1/2 and typically at least 2 [MJ/m 3 ] 1/2 .
  • the difference between the solubility parameter of the curable binder and the diluent is preferably at least 3 [MJ/m 3 ] 1/2 , 4 [MJ/m 3 ] 1/2 , or 5 [MJ/m 3 ] 1/2 .
  • the difference between the solubility parameter of the curable binder and the diluent is more preferably at least 6 [MJ/m 3 ] 1/2 , 7 [MJ/m 3 ] 1/2 , or 8 [MJ/m 3 ] 1/2 .
  • Various organic diluents can be employed depending on the choice of curable organic binder.
  • suitable diluents include various alcohols and glycols such as alkylene glycol (e.g. ethylene glycol, propylene glycol, tripropylene glycol), alkyl diol (e.g. 1, 3 butanediol,), and alkoxy alcohol (e.g. 2-hexyloxyethanol, 2-(2-hexyloxy)ethanol, 2-ethylhexyloxyethanol); ethers such as dialkylene glycol alkyl ethers (e.g.
  • diethylene glycol monoethyl ether dipropylene glycol monopropyl ether, tripropylene glycol monomethyl ether
  • esters such as lactates and acetates and in particular dialkyl glycol alkyl ether acetates (e.g. diethylene glycol monoethyl ether acetate); alkyl succinate (e.g. diethyl succinate), alkyl glutarate (e.g. diethyle glutarate), and alkyl adipate (e.g. diethyl adipate).
  • the glass- or ceramic- forming particulate material (e.g. powder) is chosen based on the end application of the microstructures and the properties of the substrate to which the microstructures will be adhered.
  • One consideration is the coefficient of thermal expansion (CTE) of the substrate material (e.g. glass panel of PDP).
  • CTE of the glass- or ceramic- forming material of the slurry of the present invention differs from the CTE of the substrate material (e.g. electrode patterned glass panel of a PDP) by no more than 10%.
  • the substrate material has a CTE which is much less than or much greater than the CTE of the ceramic material of the microstructures, the microstructures can warp, crack, fracture, shift position, or completely break off from the substrate during processing.
  • Inorganic particulate materials suitable for use in the slurry of the present invention preferably have coefficients of thermal expansion of about 5 X 10 "6 /°C to 13 X 10 "6 /°C .
  • Glass and/or ceramic materials suitable for use in the slurry of the present invention typically have softening temperatures below about 600 0 C, and usually above 400 0 C.
  • the softening temperature of the ceramic powder indicates a temperature that must be attained to fuse or sinter the material of the powder.
  • the substrate generally has a softening temperature that is higher than that of the ceramic material of the rib precursor. Choosing a glass and/or ceramic powder having a low softening temperature allows the use of a substrate also having a relatively low softening temperature.
  • Suitable composition include for example i) ZnO and B2O3; ii) BaO and B2O3; iii) ZnO, BaO, and B2O3; iv) La 2 ⁇ 3 and B2O3; and v) AI2O3, ZnO, and P2O5.
  • Lower softening temperature ceramic materials can be obtained by incorporating certain amounts of lead, bismuth, or phosporous into the material.
  • Other low softening temperature ceramic materials are known in the art.
  • Other fully soluble, insoluble, or partially soluble components can be incorporated into the ceramic material of the slurry to attain or modify various properties.
  • the preferred size of the particulate glass- or ceramic- forming material of the rib precursor depends on the size of the microstructures to be formed and aligned on the patterned substrate.
  • the average size, or diameter, of the particles is typically no larger than about 10% to 15% the size of the smallest characteristic dimension of interest of the microstructures to be formed and aligned.
  • the average particle size for PDP barrier ribs is typically no larger than about 2 or 3 microns.
  • the photocurable polymerizable compositions for use in making the mold or for use as a binder in making the ceramic microstructures preferably comprises one or more photoinitiators at a concentrations ranging from 0.05 wt-% to 5 wt-% of the polymerizable resin composition.
  • Suitable photoinitiators include for example, 2-hydroxy-2-methyl-l- phenylpropane- 1 -one; 1 -[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy -2 -methyl- 1 -propane- 1 - one; 2,2-dimethoxy-l ,2-diphenylethane- 1 -one; 2-methyl- 1 -[4-(methylthio)phenyl]-2- morpholino-1-propanone; and mixtures thereof.
  • Suitable photoinitiator combinations are described in U.S. Patent No. 6843952 and pending U.S. Patent Application Serial No.
  • Support Preconditioning A 22 degree C / 55%
  • Support Preconditioning B 22 degree C / 58% RH
  • a master tool having lattice type PDP barrier rib pattern in was prepared.
  • a rectangular transfer mold was made from a metal master tool, using silicone material and a stainless steel substrate, as described in WO2005/013308 and published U.S. Patent Application No. U.S. 2005/0206034-A1.
  • the cell pitch was 0.270 mm in the direction of the longer side and 0.808 mm in the direction of the shorter side.
  • a photocurable resin for use as the shape-imparting layer of the mold was prepared as follows:
  • the viscosity of the resin was 10,000 cps (Brookfield viscometer with No.5 spindle at 20 rpm rotation speed).
  • this resin was coated onto the microstructured surface of the tool such that the recesses of the microstructured surface were filled.
  • Each of the preconditioned polyester films were laminated to the photocurable resin filled tool surface in an environment having the same temperature and relative humidity as used to precondition the PET support film.
  • a low pressure mercury lamp (Chemical lamp, the irradiation wave length: 300-400nm, manufactured by Mitsubishi Osram)
  • the resin was photocured with 3,000 mJ/cm 2 of UV irradiated through the preconditioned polyester film support. Then the mold was removed from the tool.

Abstract

La présente invention concerne un procédé de fabrication d'un moule flexible avec un support hygroscopique, le moule flexible, ainsi que des procédés d'utilisation du moule pour fabriquer des microstructures.
PCT/US2007/085997 2006-12-07 2007-11-30 Procédé de moulage de nervures barrières à l'aide de moules à base de matériaux polymériques hygroscopiques WO2008073719A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US86898106P 2006-12-07 2006-12-07
US60/868,981 2006-12-07

Publications (1)

Publication Number Publication Date
WO2008073719A1 true WO2008073719A1 (fr) 2008-06-19

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Application Number Title Priority Date Filing Date
PCT/US2007/085997 WO2008073719A1 (fr) 2006-12-07 2007-11-30 Procédé de moulage de nervures barrières à l'aide de moules à base de matériaux polymériques hygroscopiques

Country Status (2)

Country Link
TW (1) TW200903570A (fr)
WO (1) WO2008073719A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6352763B1 (en) * 1998-12-23 2002-03-05 3M Innovative Properties Company Curable slurry for forming ceramic microstructures on a substrate using a mold
US20030100192A1 (en) * 2001-10-09 2003-05-29 3M Innovative Properties Company Method for forming ceramic microstructures on a substrate using a mold and articles formed by the method
US20050212182A1 (en) * 2002-07-17 2005-09-29 Chikafumi Yokoyama Flexible mold and method of manufacturing microstructure using same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6352763B1 (en) * 1998-12-23 2002-03-05 3M Innovative Properties Company Curable slurry for forming ceramic microstructures on a substrate using a mold
US20030100192A1 (en) * 2001-10-09 2003-05-29 3M Innovative Properties Company Method for forming ceramic microstructures on a substrate using a mold and articles formed by the method
US20050212182A1 (en) * 2002-07-17 2005-09-29 Chikafumi Yokoyama Flexible mold and method of manufacturing microstructure using same

Also Published As

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TW200903570A (en) 2009-01-16

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