Abstract: The present invention relates to a norbornene based addition polymer, and more particularly to an addition polymer of norbornene based monomers containing an ester group. The present invention provides a norbornene-ester based addition polymer having a molecular weight (Mn) larger than 20,000 and comprising a norbornene-ester based monomer comprising more than 50 mol % of exo norbornene-ester monomer as a repeating unit, a method for preparing the same, and an optically anisotropic film comprising the same. The norbornene-ester based addition polymer of the present invention is transparent, has a low dielectric constant, has good thermal stability and strength, leaves no unwanted materials when attached to metals or other polymers, and has good adhesivity, so that it can be used for optical films, retardation films, plastic substrate materials, transparent polymers such as POF or PCB, insulating materials, or insulating electronic devices such as PCB or insulating materials.

Abstract: The present invention relates to a catalyst system for preparing a cyclic olefin addition polymer, a method for preparing the catalyst system and a cyclic olefin addition polymer prepared by the method, and more particularly to the method comprising the steps of contacting some content of norbornene-based monomer having a specific polar functional group with a catalyst system comprising a) a Group X transition metal compound; b) a compound comprising a neutral Group XV electron donor ligand having a cone angle of at least 160°; and c) a salt capable of offering an anion that can be weakly coordinated to the transition metal of the a) the Group X transition metal compound.

Abstract: The present invention relates to a method for preparing a cyclic olefin polymer by addition polymerization, and more particularly to a method for preparing a norbornene-based addition polymer, which comprises a step of contacting a norbornene-based monomer having an ester or acetyl group with a catalyst system comprising: a Group X transition metal compound; a compound comprising a neutral Group XV electron donor ligand having a cone angle of at least 160°; and a salt capable of offering an anion that can be weakly coordinated to the transition metal, in solvent. The norbornene-based addition polymer having an ester or acetyl group according to the present invention is transparent, has superior adhesivity and a low dielectric constant, and it generates no byproducts when attached to metal. Therefore, it can be used as an optical film, a retardation film, a protection film for a polarizer, POFs (plastic optical fiber), PCBs (printed circuit board), or insulators of electronic devices.

Abstract: A microlens array sheet and a manufacturing method thereof. The microlens array sheet comprises: a transparent substrate; bases formed on the transparent substrate, the bases having the same height as a result of a planarization process conducted for the upper portions of the bases, microlenses formed on the bases; and a gap-filling film applied on the resulting structure, in which the bases have the same height. The method comprises the steps of: depositing base-forming molds on a transparent support substrate or film and loading a material to be used as bases between the base-forming molds; polishing the upper portion of the material for use as bases so as to form bases having the same level, and removing the base-forming molds; depositing microlenses on the formed bases; and depositing a gap-filling film on the resulting structure.

Abstract: Disclosed is a microlens array sheet capable of improving a viewing angle by maintaining a fill factor while reducing a radius of curvature of the microlens of the microlens array sheet. To this end, the microlens array sheet includes: a substrate; a lens arranged on the substrate; and a gap filling layer formed at exposed surfaces of the substrate and the lens, wherein the lens is arranged as high as or at a higher position than a height of the gap filling layer formed at a gap between lenses arranged on the substrate.

Abstract: Disclosed is a method for preparing a cycloolefin polymer containing polar functional groups, comprising the steps of: a) preparing a catalyst mixture including i) a precatalyst; ii) a first cocatalyst; and iii) a second cocatalyst; and b) subjecting a monomer solution comprising a norbornene-based compound containing a polar functional group to an addition polymerization reaction in the presence of an organic solvent and the catalyst mixture, wherein the product yield of the prepared polymer is 50% by weight or more based on the total weight of the monomer.

Abstract: Disclosed herein are a microlens array sheet using micro machining and a method for manufacturing the same. The microlens array sheet comprises a microlens array having a convex and concave surface including curved portions and boundary grooves formed between respective neighboring microlenses via laser micro machining, and a void filler layer stacked on the microlens array. The microlens array sheet can be manufactured with a reduced number of process steps using laser micro machining, whereby improved productivity as compared to a conventional sequential semiconductor process can be accomplished. Using the laser micro machining, also, enables the manufacture of a desired three-dimensional micro shape. Therefore, the microlens array sheet is applicable as an optical sheet of a display system requiring a delicate surface shape.

Abstract: A variable optical attenuator for optical communications comprises: a substrate on which a plurality of alignment grooves are patterned; an input optical fiber aligned in one of the alignment grooves and receiving an optical signal; a reflector formed on the substrate so as to move to change a path of an optical signal which has passed through the input optical fiber; an output optical fiber aligned in one of the alignment grooves and outputting an optical signal whose path has been changed; a first lens aligned in one of the alignment grooves between the input/output optical fibers and the reflector so as to collimate an optical signal in a direction perpendicular to the substrate; and a second lens patterned on the substrate between the input/output optical fibers and the reflector so as to collimate an optical signal in a direction horizontal to the substrate, thereby facilitating an assembly process, reducing an alignment error, and miniaturizing its entire size.

Abstract: Disclosed is a front filter of a display panel and its fabrication method capable of improving optical performance by using an image display microlens array sheet. A front filter of a display panel for performing shielding of an electro-magnetic wave emitted from the display panel and optical compensation, includes a microlens array sheet reducing light diffusion by refracting light emitted from the display panel.

Abstract: Disclosed herein are a microlens array sheet and a manufacturing method thereof. The microlens array sheet comprises: a transparent substrate to be arrayed with microlenses; bases formed on the transparent substrate to a height determined by a user, the bases being formed at the same positions as microlenses to be formed later; microlenses formed on the bases; and a gap-filling film applied on the resulting structure, in which the bases have the same height as a result of a planarization process conducted for the upper portion of the bases.

Abstract: Disclosed herein are a microlens array sheet having a black matrix and a method for manufacturing the same. The manufacturing method includes a) the step of defining the regions of light apertures, through which condensed light passes, in a negative-type light-sensitive resin layer by radiating and condensing parallel light after sequentially laying a microlens array layer, a transparent support substrate or film layer and the negative-type light-sensitive resin layer one on top of another, and b) eliminating portions other than the regions of the light apertures formed in the light-sensitive resin layer, and forming a black matrix layer in regions where the portions have been eliminated.

Abstract: Disclosed herein is a projection screen having a microlens array. The projection screen includes a substrate, a light blocking layer, a light diffusion layer, and a protection layer. The substrate is formed to mount a plurality of microlenses thereon. A microlens array is formed of the microlenses that are arranged and formed on the entire surface of the substrate. The light blocking layer is formed on the rear of the surface on which the microlens array of the substrate is formed. The light diffusion layer is formed on the bottom of the light blocking layer. The protection layer is formed on the bottom of the light diffusion layer.

Abstract: The present invention relates to a unified polarizing plate, which employs, as a protection layer of a polarizing film, a transparent film that can simultaneously function as a negative C-plate and transparent protection layer of a polarizing film and has negative refractive index toward thickness direction, thereby simultaneously performing functions as a negative C-plate for optical compensation and as a polarizing plate, and a method for preparing the same. The unified polarizing plate has superior durability at high temperature and high humidity compared to those employing TAC as a protection layer, and improves wide view angle of liquid crystal display having positive refractive index toward thickness direction, when the liquid crystal display device is ON or OFF.

Abstract: Disclosed is a microlens array sheet capable of improving a viewing angle by maintaining a fill factor while reducing a radius of curvature of the microlens of the microlens array sheet. To this end, the microlens array sheet includes: a substrate; a lens arranged on the substrate; and a gap filling layer formed at exposed surfaces of the substrate and the lens, wherein the lens is arranged as high as or at a higher position than a height of the gap filling layer formed at a gap between lenses arranged on the substrate.

Abstract: Provided are a vertically aligned liquid crystal display (VA-LCD) with good viewing angle characteristics, which has liquid crystals with negative dielectric anisotropy (??<0). In the VA-LCD, a polynorbornene based polymer film is used as a protection film and/or as a negative C-plate retardation film for an upper polarization plate and/or a lower polarization plate. Therefore, high contrast characteristics for a front view and an oblique angle view are realized and color change for an oblique angle view can be minimized.

Abstract: A variable optical attenuator for optical communications comprises: a substrate on which a plurality of alignment grooves are patterned; an input optical fiber aligned in one of the alignment grooves and receiving an optical signal; a reflector formed on the substrate so as to move to change a path of an optical signal which has passed through the input optical fiber; an output optical fiber aligned in one of the alignment grooves and outputting an optical signal whose path has been changed; a first lens aligned in one of the alignment grooves between the input/output optical fibers and the reflector so as to collimate an optical signal in a direction perpendicular to the substrate; and a second lens patterned on the substrate between the input/output optical fibers and the reflector so as to collimate an optical signal in a direction horizontal to the substrate, thereby facilitating an assembly process, reducing an alignment error, and miniaturizing its entire size.

Abstract: A micro collimating lens system for optical communication includes: an optical fiber aligned on a silicon substrate in a certain direction for transmitting an optical signal; and at least two lenses aligned on the silicon substrate in order that the optical signal can be collimated at multiple stages, so that efficiency in assembling the lens system for collimating the optical signal is improved and a fabrication cost is reduced.

Abstract: Disclosed is a method for preparing a cycloolefin polymer containing polar functional groups, comprising: preparing a catalyst mixture including i) a precatalyst, containing a Group 10 transition metal having a ligand containing oxygen ions bonded to the metal; ii) a first cocatalyst which is an organic compound containing a Group 15 element; and iii) a second cocatalyst which is capable of providing an anion and weakly coordinating to the metal of the precatalyst; and subjecting a monomer solution comprising a norbornene-based compound containing a polar functional group to an addition polymerization reaction in the presence of an organic solvent and the catalyst mixture, at a temperature of 80-200° C., the total amount of the organic solvent being 50-800% by weight based on the total weight of the monomer contained in the monomer solution, and the product yield of the polymer being 50% by weight or more based on the total weight of the monomer.

Abstract: The present invention provides a negative C-plate type optical anisotropic film having negative birefringence along the thickness direction. In particular, the present invention provides n film comprising cycloolefin addition polymer, which is prepared by addition polymerizing norbornene-based monomers, a method for preparing the same, and a liquid crystal display comprising the same. The film of the present invention can be used for optical compensation films of a variety of LCD (liquid crystal display) modes because the refractive index alone the thickness direction can be controlled by the kind and amount of functional groups introduced to the cycloolefin addition polymer.

Abstract: The present invention relates to a norbornene based addition polymer, and more particularly to an addition polymer of norbornene based monomers containing an ester group. The present invention provides a norbornene-ester based addition polymer having a molecular weight (Mn) larger than 20,000 and comprising a norbornene-ester based monomer comprising more than 50 mol % of exo norbornene-ester monomer as a repeating unit, a method for preparing the same, and an optically anisotropic film comprising the same. The norbornene-ester based addition polymer of the present invention is transparent, has a low dielectric constant, has good thermal stability and strength, leaves no unwanted materials when attached to metals or other polymers, and has good adhesivity, so that it can be used for optical films, retardation films, plastic substrate materials, transparent polymers such as POF or PCB, insulating materials, or insulating electronic devices such as PCB or insulating materials.