Abstract: A polishing sheet includes a sheet including one side having a surface, a plurality of convex portions provided to project from the surface of the one side of the sheet, a plurality of first abrasive grains provided on an upper surface of each of the convex portions, and a plurality of second abrasive grains provided on the surface of the sheet. The second abrasive grains each have hardness higher than that of the first abrasive grains.

Abstract: A polishing sheet comprising a plurality of convex portions which protrudes from a sheet surface and includes an upper surface which is in parallel to the sheet surface is disclosed. A plurality of abrasive grains made by a granular porous body in which a number of primary particles are partially bonded to each other and include a void in between is arranged at least on the upper surface of the convex portion.

Abstract: A polishing sheet includes a sheet including one side having a surface, a plurality of convex portions provided to project from the surface of the one side of the sheet, a plurality of first abrasive grains provided on an upper surface of each of the convex portions, and a plurality of second abrasive grains provided on the surface of the sheet. The second abrasive grains each have hardness higher than that of the first abrasive grains.

Abstract: A polishing sheet comprising a plurality of convex portions which protrudes from a sheet surface and includes an upper surface which is in parallel to the sheet surface is disclosed. A plurality of abrasive grains made by a granular porous body in which a number of primary particles are partially bonded to each other and include a void in between is arranged at least on the upper surface of the convex portion.

Abstract: An abrasive grain includes a granular porous body in which many primary grains are bonded with each other partially, and in a state where pores are formed, and a functionalizing material which is constituted of a material which is different from the primary grains is contained within the abrasive grain.

Abstract: A nozzle plate includes a nozzle base; a nozzle hole to discharge droplets and formed on the nozzle base; and a water-repellent film formed on at least a liquid discharging surface of the nozzle base. The nozzle base is formed of a stainless material that includes a surface layer area on which the water-repellent film is formed. The surface layer area has a higher chrome density than the chrome density of the stainless material itself, and a ratio of Cr to Fe (Cr/Fe) in the surface layer area is equal to and more than 0.8. The nozzle plate production method as such includes polishing with a polishing agent a surface of the nozzle base; removing Fe in a surface layer area of the stainless material by etching using a polishing agent; and combining chrome with oxygen.

Abstract: A nozzle plate includes a nozzle base; a nozzle hole to discharge droplets and formed on the nozzle base; and a water-repellent film formed on at least a liquid discharging surface of the nozzle base. The nozzle base is formed of a stainless material that includes a surface layer area on which the water-repellent film is formed. The surface layer area has a higher chrome density than the chrome density of the stainless material itself, and a ratio of Cr to Fe (Cr/Fe) in the surface layer area is equal to and more than 0.8. The nozzle plate production method as such includes polishing with a polishing agent a surface of the nozzle base; removing Fe in a surface layer area of the stainless material by etching using a polishing agent; and combining chrome with oxygen.

Abstract: A method of molding an object with a mold having a transfer face includes the steps of filling, separating, re-melting, re-contacting, cooling, and removing. The filling step fills a thermoplastic material, having a temperature greater than a softening temperature of the thermoplastic material, into a cavity space in the mold having a temperature smaller than the softening temperature of the thermoplastic material. The thermoplastic material comes in contact with the transfer face and is cooled. The separating step separates the transfer face from the thermoplastic material to form a heat-insulating layer between the thermoplastic material and transfer face. The re-melting step re-melts the thermoplastic material with heat energy retained inside the thermoplastic material. The re-contacting step re-contacts the re-melted thermoplastic material to the transfer face. The cooling step cools the thermoplastic material to a temperature smaller than the softening temperature of the thermoplastic material.

Abstract: A method of molding an object with a mold having a transfer face includes the steps of filling, separating, re-melting, re-contacting, cooling, and removing. The filling step fills a thermoplastic material, having a temperature greater than a softening temperature of the thermoplastic material, into a cavity space in the mold having a temperature smaller than the softening temperature of the thermoplastic material. The thermoplastic material comes in contact with the transfer face and is cooled. The separating step separates the transfer face from the thermoplastic material to form a heat-insulating layer between the thermoplastic material and transfer face. The re-melting step re-melts the thermoplastic material with heat energy retained inside the thermoplastic material. The re-contacting step re-contacts the re-melted thermoplastic material to the transfer face. The cooling step cools the thermoplastic material to a temperature smaller than the softening temperature of the thermoplastic material.

Abstract: A plastic molding having high accuracy includes at least one transfer surface and at least one imperfect transfer portion having a concave or convex shape. The mold assembly includes a cavity into which molten resin is injected, a slide cavity piece which is capable of being slid at a prescribed time so that a gap is formed between the resin and the slide cavity piece, and a vent hole for supplying a compressed gas in the cavity. A method of producing the plastic molding includes the steps of heating resin to provide a molten resin, injecting the molten resin into a cavity of a molding, applying a resin-pressure to the molten resin, cooling the resin, sliding the slide cavity piece, and opening the mold assembly.

Abstract: A plastic optical element producing method produces a plastic optical element by an injection molding, and includes the step of cooling the optical element to a room temperature to cool an optical surface of the plastic optical element with priority over other surfaces of the plastic optical element in a state where a temperature of the plastic optical element is within a predetermined temperature range which is less than or equal to a glass transition temperature of the resin material.

Abstract: A method for manufacturing an optical element, such as a plastic lens or similar, by molding. The manufacturing method includes the steps of molding the plastic lens under a prescribed molding temperature higher than a glass transition level of the plastic material used to from the optical element. The manufacturing method also includes the step of gradually cooling the optical element by at least 5° C. with a speed which decreases by approximately 3° C. per minute. The optical element formed from a plastic material includes a substantially rectangular shape having a width, a height, and a thickness, wherein the width is greater than the height and the thickness is measured in an optical axis direction. The optical element also includes a refractive index distribution of approximately 2×10?5 at a central half section of the height. The optical element may be defined by the manufacturing method having the molding step and the gradual cooling step.

Abstract: A method of producing a molding by injection molding, wherein only a part of the molding expected to sink is surely caused to sink while, e.g., a mirror surface is surely transferred to a desired part of the molding.

Abstract: A plastic molding for use in an optical device, a method of producing the molding by injection molding, and an apparatus for practicing the method are disclosed. Only a part of a molding expected to sink is surely caused to sink while, e.g., a mirror surface is surely transferred to a desired part of the molding.

Abstract: An apparatus for producing a plastic molded article or product for use in an optical device is a mold assembly. The mold assembly includes a pair of molds having an inner mold surface forming a cavity with a preselected volume into which a molten molding material is injected via a gate or sprue to fill the cavity and thereby form a molded product having a sink surface and at least one mirror surface after the molten molding material has cooled. The inner mold surface includes at least one transfer surface portion against which the at least one mirror surface of the molded product is formed, and at least one non-transfer surface portion against which the sink surface portion of the molded product is formed. The mold assembly also includes at least one vent hole, at least one bore in communication with the vent hole so that a preselected air pressure is applied to the molten molding material in the cavity via the bore and the vent hole, and at least one exhaust hole adjacent to, but spaced from the vent hole.

Abstract: A method for manufacturing an optical element, such as a plastic lens or similar, by molding. The manufacturing method includes the steps of molding the plastic lens under a prescribed molding temperature higher than a glass transition level of the plastic material used to from the optical element. The manufacturing method also includes the step of gradually cooling the optical element by at least 5° C. with a speed which decreases by approximately 3° C. per minute. The optical element formed from a plastic material includes a substantially rectangular shape having a width, a height, and a thickness, wherein the width is greater than the height and the thickness is measured in an optical axis direction. The optical element also includes a refractive index distribution of approximately 2×10−5 at a central half section of the height. The optical element may be defined by the manufacturing method having the molding step and the gradual cooling step.

Abstract: A plastic molding having high accuracy includes at least one transfer surface and at least one imperfect transfer portion having a concave or convex shape. The mold assembly includes a cavity into which molten resin is injected, a slide cavity piece which is capable of being slid at a prescribed time so that a gap is formed between the resin and the slide cavity piece, and a vent hole for supplying a compressed gas in the cavity. A method of producing the plastic molding includes the steps of heating resin to provide a molten resin, injecting the molten resin into a cavity of a molding, applying a resin-pressure to the molten resin, cooling the resin, sliding the slide cavity piece, and opening the mold assembly.

Abstract: A method for manufacturing an optical element, such as a plastic lens or similar, by molding. The manufacturing method includes the steps of molding the plastic lens under a prescribed molding temperature higher than a glass transition level of the plastic material used to from the optical element. The manufacturing method also includes the step of gradually cooling the optical element by at least 5° C. with a speed which decreases by approximately 3° C. per minute. The optical element formed from a plastic material includes a substantially rectangular shape having a width, a height, and a thickness, wherein the width is greater than the height and the thickness is measured in an optical axis direction. The optical element also includes a refractive index distribution of approximately 2×10−5 at a central half section of the height. The optical element may be defined by the manufacturing method having the molding step and the gradual cooling step.

Abstract: A plastic optical element producing method produces a plastic optical element by an ejection molding, and includes the step of cooling an optical surface of the plastic optical element with priority in a state where a temperature of the plastic optical element is within a predetermined temperature range which is less than or equal to a glass transition temperature of the resin material.

Abstract: A plastic molding for use in an optical device, a method of producing the molding by injection molding, and an apparatus for practicing the method are disclosed. Only a part of a molding expected to sink is surely caused to sink while, e.g., a mirror surface is surely transferred to a desired part of the molding.