Patent Application
20140300011
1. Technical Field
The present disclosure relates to an apparatus for manufacturing an optical film, and a method for manufacturing the optical film using the apparatus.
2. Description of Related Art
Optical films are used in backlight modules for guiding light. Opposite surfaces of a typical optical film comprise a number of microstructures. The optical film can be manufactured by a rolling device. The rolling device comprises two pressing rollers with microstructures formed on circumferential surfaces thereof. The pressing rollers are arranged side-by-side, and are driven to press opposite surfaces of an unprocessed optical film to mold the microstructures of the optical film.
However, a molding route of the microstructures of the pressing rollers is relatively short. As a result, the shapes of the microstructures molded on the surfaces of the optical film may not be fully formed. When this happens, a brightness of the backlight module employing the optical film is reduced.
Therefore, it is desirable to provide an apparatus for manufacturing an optical film and a method for manufacturing an optical film using the apparatus to overcome the above-mentioned problems.
The feeder 10 is substantially funnel-shaped and comprises a pipe 102. The feeder 10 is configured for providing a resin 101 in hot melted form through the pipe 102.
The platen 20 comprises a smooth circumferential surface 201, and a number of cooling pipes 35. The cooling pipes 35 are arranged around a central axis of the platen 20.
The first pressing roller group 30 and the platen 20 are arranged under the feeder 10 and spaced a predetermined distance from each other. A first pressing roller 31 of the first pressing roller group 30 and the platen 20 define a guiding channel 310 therebetween. A width of the guiding channel 310 determines a thickness of the optical film 101a. The first pressing roller group 30 comprises the first pressing roller 31 defining a first central axis O1, a second pressing roller 32 defining a second central axis O2, a first rotating band 33, and a first intermediate roller 34. The first central axis O1 and the second central axis O2 are arranged on a common horizontal plane and are substantially parallel to each other. The first rotating band 33 is wound around the first pressing roller 31 and the second pressing roller 32. The first pressing roller 31 and the second pressing roller 32 cooperatively rotate the first rotating band 33. The first intermediate roller 34 is arranged between the first pressing roller 31 and the second pressing roller 32, and contacts the first rotating band 33. The first intermediate roller 34 has a central axis. As the first rotating band 33 rotates around the first pressing roller 31 and the second pressing roller 32, the first intermediate roller 34 rotates around its central axis. The first intermediate roller 34 is configured for enhancing accurate formation of pressed microstructures on a top surface of the pressed resin 101.
The second pressing roller group 40 is spaced the predetermined distance from the first pressing roller group 30 to form a molding channel 401. The second pressing roller group 40 comprises a third pressing roller 41 defining a third central axis O3, a fourth pressing roller 42 defining a fourth central axis O4, and a second rotating band 43. The third central axis O3 and the fourth central axis O4 are arranged on a common horizontal plane and are substantially parallel to each other. The second rotating band 43 is wound around the third pressing roller 41 and the fourth pressing roller 42. The third pressing roller 41 and the fourth pressing roller 43 cooperatively rotate the second rotating band 43. The first rotating band 33 and the second rotating band 43 are made of metal, but can be made of other suitable material in other embodiments. The second intermediate roller 44 is arranged between the third pressing roller 41 and the fourth pressing roller 42, and contacts the second rotating band 43. The second intermediate roller 44 has a central axis. As the second rotating band 43 rotates around the third pressing roller 41 and the fourth pressing roller 42, the second intermediate roller 44 rotates around its central axis. The second intermediate roller 44 is configured for enhancing accurate formation of the pressed microstructures on the top surface of the pressed resin 101.
The first rotating band 33 comprises a first inner surface (not labeled) and a first outer surface 330. The first inner surface comprises a number of first convex gear structures 333, and the first outer surface 330 comprises a number of first microstructures 332. The first convex gear structures 333 can be in the form of gear teeth. Each of the first microstructures 332 is substantially round. For example, each first microstructure 332 can be a hemisphere, or an elongated bar with a semicircular cross-section. The second rotating band 43 comprises a second inner surface (not labeled) and a second outer surface 430. The second inner surface comprises a number of second convex gear structures 433, and the second outer surface 430 is a smooth surface. The second convex gear structures 433 can be in the form of gear teeth.
Outer circumferential surfaces of the first pressing roller 31 and the second pressing roller 32 define a number of first concave gear structures 321 corresponding to the first convex gear structures 333 of the first rotating band 33. The first concave gear structures 321 can be in the form of gear recesses. Outer circumferential surfaces of the third pressing roller 41 and the fourth pressing roller 42 define a number of second concave gear structures 421 corresponding to the second convex gear structures 433 of the second rotating band 43. The second concave gear structures 421 can be in the form of gear recesses. The concave gear structures 321, 421 and the convex gear structures 333, 433 are configured for preventing the first and second rotating bands 33, 43 from sliding when rotating.
The first pressing roller 31, the second pressing roller 32, the third pressing roller 41, and the fourth pressing roller 42 each comprise a number of the cooling pipes 35, which are arranged around central axes thereof. The cooling pipes 35 receive cooling water for cooling the hot resin 101 and thereby molding the cooled resin 101 into the optical film 101a quickly.
The pinch rollers 50 are arranged adjacent to rear ends of the first pressing roller group 30 and the second pressing roller group 40, and are configured and arranged for adjusting a strain on the optical film 101a. The pinch rollers 50 are used for preventing the optical film 101a from warping. In this embodiment, there are three pinch rollers 50.
The hot melted resin 101 from the feeding hopper 10 flows into the guiding channel 310 and is cooled and pressed by the platen 20 and the first pressing roller group 30. The cooled resin 101 is then rolled into the molding channel 401 with rolling of the first pressing roller group 30. The first pressing roller group 30 and the second pressing roller group 40 cooperatively roll the pressed resin 101 through the molding channel 401. The first pressing roller group 30 presses the first microstructures 332 on the top surface of the pressed resin 101 to form the optical film 101a.
The winding roller 60 is substantially a hollow cylinder, and is configured for winding the optical film 101a. Each pinch roller 50 defines a fifth central axis (not shown) in a central portion thereof. The winding roller 60 defines a sixth central axis (not shown) in a central portion thereof
Referring to
In step S1, the feeder 10, the platen 20, the first pressing roller group 30, and the second pressing roller group 40 are provided.
In step S2, the platen 20, the first pressing roller group 30, and the second pressing roller group 40 are rotated. A rotating direction of the platen 20 is opposite to a rotating direction of the first pressing roller group 30, and the rotating direction of the first pressing roller group 30 is opposite to a rotating direction of the second pressing roller group 40. In this embodiment, the platen 20 and the second pressing roller group 40 rotate clockwise, and the first pressing roller group 30 rotates counterclockwise.
In step S3, the hot melted resin 101 is introduced into the guiding channel 310 and cooled and pressed by the platen 20 and the first pressing roller group 30. The cooled resin 101 is then rolled into the molding channel 401 with rolling of the first pressing roller group 30. Then the cooled resin 101 is rolled through the molding channel 401 cooperatively by the first pressing roller group 30 and a second pressing roller group 40a. The first pressing roller group 30 presses the first microstructures 332 on a first (top) surface of the cooled resin 101, and the second pressing roller group 40a presses the second microstructures 432 on a second (bottom) surface of the cooled resin 101. Thereby, microstructures are formed on the first surface and the second surface of the optical film 101c. Then, the optical film 101c is wound around the winding roller 60. The resin 101 can be made of polystyrene, polymethyl methacrylate, polycarbonate, or UV-curable glue. However, the resin 101 is not limited to being made of these materials.
In summary, the above-described apparatuses and method are used for manufacturing an optical film, including forming microstructures on the optical film. A processing route of the formed microstructures is longer, and the microstructures can be formed on the first and/or second surfaces completely without defects.
It is to be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in the matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102112079 | Apr 2013 | TW | national |
