Plastic and nonmetallic article shaping or treating: processes – Optical article shaping or treating – Light polarizing article or holographic article
Reexamination Certificate
2001-12-05
2004-05-25
Colaianni, Michael (Department: 1734)
Plastic and nonmetallic article shaping or treating: processes
Optical article shaping or treating
Light polarizing article or holographic article
C264S002700
Reexamination Certificate
active
06740265
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates a method and an apparatus for peeling a lens sheet such as a Fresnel lens sheet from a forming mold.
2. Description of the Related Art
Japanese Laid-Open Patent Application Nos. S64-86102, H6-67002 and H7-148751 disclose a method for manufacturing various kinds of lens sheet such as Fresnel lens sheets, lenticular lens sheets or the like, which are to be used for a transmission type screen for a projection TV.
According to the manufacturing method, which is disclosed in Japanese Laid-Open Patent Application No. S64-86102, a lens sheet is manufactured by carrying out the following steps. First, ultraviolet ray curing type resin in the form of liquid is applied on the entirety of the upper surface of a forming mold to form an uncured resin layer. Then, the ultraviolet ray curing type resin in the form of liquid is applied on one side of the uncured resin layer to form an uncured resin pool. Then, a sheet-shaped substrate is placed on the uncured resin pool. The uncured resin pool and the uncured resin layer are pressed together with the substrate against the forming mold by means of a pressing roller from the above-mentioned one side of the uncured resin layer toward the other side thereof so as to obtain a laminate structure of the substrate and the ultraviolet ray curing type resin, while excluding bubbles from the ultraviolet ray curing type resin. Then, ultraviolet ray is irradiated on the ultraviolet ray curing type resin through the substrate to cure it. Then, the cured resin is peeled together with the substrate from the forming mold, thus manufacturing a lens sheet.
According to the manufacturing method, which is disclosed in Japanese Laid-Open Patent Application No. H6-67002, a lens sheet is manufactured by carrying out the following steps. First, ultraviolet ray curing type resin in the form of liquid is applied on the entirety of the upper surface of a forming mold to form an uncured resin layer. Ultraviolet ray is irradiated on the uncured resin layer to cure it. The ultraviolet ray curing type resin is further applied on one side, i.e., a pressing-starting side of the cured resin layer to form an uncured resin pool. Then, the thus applied ultraviolet curing type resin is spread through a sheet-shaped substrate into a uncured resin layer by means of a pressing roller so as to obtain a laminate structure of the substrate, the cured resin layer and the uncured resin layer, while excluding bubbles from the ultraviolet ray curing type resin. Then, the ultraviolet ray is irradiated on the uncured resin layer through the substrate to cure it. Then, the cured resin is peeled together with the substrate from the forming mold, thus manufacturing a lens sheet.
According to the manufacturing method, which is disclosed in Japanese Laid-Open Patent Application No. H7-148751, a lens sheet is manufactured by carrying out the following steps. First, ultraviolet ray curing type resin in the form of liquid is applied on the entirety of the upper surface of a forming mold to form an uncured resin layer. Solvent contained in the ultraviolet ray curing type resin is vaporized by a hot-air dryer to form a solvent-vaporized layer. Then, the ultraviolet ray curing type resin is applied on one side, i.e., a pressing-starting side of the solvent-vaporized layer to form an uncured resin pool. Then, the uncured resin pool is spread through a sheet-shaped substrate into a uncured resin layer by means of a pressing roller so as to obtain a laminate structure of the substrate, the solvent-vaporized layer and the uncured resin layer, while excluding bubbles from the ultraviolet ray curing type resin. Then, the ultraviolet ray is irradiated on the uncured resin layer through the substrate to cure it. Then, the cured resin is peeled together with the substrate from the forming mold, thus manufacturing a lens sheet.
However, the above-mentioned prior art has a problem that the lens sheet may be damaged when being peeled from the forming mold.
SUMMARY OF THE INVENTION
An object of the present invention is therefore to provide a method and an apparatus for peeling a lens sheet from a forming mold, which provide a reliable peeling of the lens sheet without causing damage.
In order to attain the aforementioned object, the method of the first aspect of the present invention for peeling a lens sheet having two pairs of opposite portions from a forming mold, comprises:
a first peeling step for pulling up a pair of opposite portions of a lens sheet, which is formed on a forming mold, to peel partially said lens sheet from said forming mold;
a second peeling step for pulling up an other pair of opposite portions of said lens sheet to peel partially said lens sheet from said forming mold; and
a third peeling step for pulling up further said two pairs of opposite portions to peel entirely said lens sheet from said forming mold.
In the second aspect of the present invention, said first peeling step and said second peeling step may be conducted simultaneously.
In the third aspect of the present invention, said first peeling step and said second peeling step may be conducted at a different time.
In the fourth aspect of the present invention, said first peeling step may be conducted by pulling up said pair of opposite portions simultaneously; and said second peeling step may be conducted by pulling up said other pair of opposite portions simultaneously.
In the fifth aspect of the present invention, said first peeling step may be conducted by pulling up said pair of opposite portions simultaneously; and said second peeling step may be conducted by pulling up said other pair of opposite portions at a different time.
In the sixth aspect of the present invention, said first peeling step may be conducted by pulling up said pair of opposite portions at a different time; and said second peeling step may be conducted by pulling up said other pair of opposite portions simultaneously.
In the seventh aspect of the present invention, said first peeling step may be conducted by pulling up said pair of opposite portions at a different time; and said second peeling step may be conducted by pulling up said other pair of opposite portions at a different time.
According to the above-mentioned features of the first to seventh aspects of the present invention, it is possible to peel smoothly the lens sheet from the forming mold, while preventing irregularities formed on the lens sheet from being coming into frictional contact with or being caught by irregularities of lens formation grooves of the forming mold. Defects or damage of the lens sheet can be prevented.
In the eighth aspect of the present invention, the method thereof may further comprise a holding step for holding a central portion of said lens sheet on said forming mold, prior to said first peeling step. According to such a feature, it is possible to peel the lens sheet from its periphery toward its central portion, thus preventing the peeling action starting from a certain peripheral position from extending through the central portion of the lens sheet to the opposite side. As a result, it is possible to reliably prevent the irregularities formed on the lens sheet from being coming into frictional contact with or being caught by the irregularities of the lens formation grooves of the forming mold.
In the ninth aspect of the present invention, said pair of opposite portions may be a pair of opposite diagonal edge portions of said lens sheet and said other pair of opposite portions may be the other pair of opposite diagonal edge portions thereof. According to such features, it is possible to catch the lens sheet to pull it up, thus performing an easy peeling operation of the lens sheet.
In the tenth aspect of the present invention, said pair of opposite portions may be a pair of opposite side portions of said lens sheet and said other pair of opposite portions may be the other pair of opposite side portions thereof. According to such features, it is possible to prevent deformation of the len
Kawamura Takashi
Matsumoto Kazuyuki
Colaianni Michael
Dai Nippon Printing Co. Ltd.
Ladas & Parry
Tadesse Yewebdar
LandOfFree
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