Patent Application
20110156293
1. Technical Field
The present disclosure generally relates to an embossing assembly, a method of manufacturing the embossing assembly, and a method of embossing light guide plates using the embossing assembly.
2. Description of Related Art
Backlight modules are critical components of a liquid crystal display, such as those used in a mobile phone or digital camera. A commonly used backlight module generally includes a light guide plate to optimize optical properties. A typical method of manufacturing the light guide plate includes forming a plurality of micro-structures on a die by precision cutting, and employing the die to form the light guide plate by insert-molding. However, the insert-molding process provides only limited manufacturing efficiency, and sprue material is unavoidably generated during the insert-molding process, indicating material waste.
A roll-to-roll process is often used to fabricate the light guide plate, providing improvements in both manufacturing efficiency and manufacturing cost. A roller for embossing arrays of structural features on a substrate, such as a plurality of micro-structures, rolls on and embosses the substrate to imprint a plurality of micro-structures thereon. Generally, the roller is provided with a plurality of micro-structures formed on the outer surface thereof. The micro-structures are commonly formed by die cutting the roller surface employing precision machine cutting. However, since the roller is substantially cylindrical, when the light guide plate to be formed has a plurality of complex micro-structures, the corresponding micro-structures on the roller are difficult to be formed by machine cutting and relatively costly.
Therefore, there is room for improvement within the art.
The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout several views, and all the views are schematic.
Referring to
The roller 11 may be made of a thermally conductive material, such as aluminum, copper, zinc, nickel, iron, titanium, cobalt or an alloy thereof. The embossing layer 12 may be made of a thin flexible layer of electroforming material, such as nickel, platinum-nickel-cobalt, cobalt-tungsten, gold or silver.
Referring to
In step S21, a plurality of predetermined micro-structures 213 is formed on a surface 212 of a plate 21 which functions as a master mold for electroforming.
The plate 21 can be made of plastic, stainless steel, paraffin or aluminium alloy. The plate 21 may be rectangular and the surface 212 of the plate 21 flat, thus facilitating the position of the plate 21 when forming the predetermined micro-structures 213. The predetermined micro-structures 213 are arranged in a matrix and may be formed by machine cutting employing a multiple spindle machine tool, laser etching, laser carving or casting. Because the predetermined micro-structures 213 are formed on a flat surface 212, a complex structure with lower manufacturing cost can be easily achieved. The predetermined micro-structures 213 formed on the plate 21 may be substantially reverse drop point-shaped, reverse prism, protrusion or groove extending along a curve.
In step S23, an embossing layer 12 with a plurality of embossing micro-structures 121 thereon is electroformed together with the plate 21 functioning as a master mold.
During the electroforming process, the plate 21 with the predetermined micro-structures 213 thereon is placed in an electrolytic bath 312 containing an electrolytic solution 311. A thin coating layer is deposited on the surface 212 of the plate 21 to form an embossing layer 12. A plurality of embossing micro-structures 121 is formed on a surface of the embossing layer 12 that is adjacent to and touches the plate 21. The embossing micro-structures 121 correspond to the predetermined micro-structures 213 on the plate 21. The embossing layer 12 may be a thin flexible layer of nickel, platinum-nickel-cobalt, cobalt-tungsten, gold or silver.
In step S25, the electroformed embossing layer 12 is detached from the plate 21. An oxidation film or graphite layer can be formed on the surface 212 of the plate 21 to facilitate removal of the embossing layer 12.
In step S27, a roller 11 is provided, and the embossing layer 12 is applied on the outer surface of the roller 11. The embossing layer 12 is secured to the roller 11 by welding, rivets, or other means.
Because a complex embossing micro-structures 121 can be easily formed by the disclosed method, corresponding complex micro-structures on the light guide plate can be formed by the embossing layer 121, thus improving the optical properties of the light guide plate.
Referring to
In step S51, an embossing substrate is provided. The embossing substrate may be a flexible thin sheet. A resin layer may be coated on a surface of the embossing substrate. The embossing substrate may be preheated before embossing.
In step S53, the embossing assembly 100 as disclosed is provided.
In step S55, the embossing layer 12 of the assembly 100 is rolled onto the embossing substrate and imprints a plurality of micro-structures corresponding to the embossing micro-structures 121 on a surface thereof. The micro-structures formed on the embossing substrate may be substantially reverse drop point-shaped, reverse prism, protrusion or groove extending along a curve matching the embossing micro-structures 121.
In step S57, the micro-structures embossed on the embossing substrate are hardened. The micro-structures can be hardened by UV radiation or heat.
In step S59, the embossing substrate with micro-structures formed thereon is cut to achieve a desired dimension to form a light guide plate (not shown).
The disclosed method allows continuous embossing of the light guide plate, thus achieving a higher manufacturing efficiency and lower cost. The disclosed method using a roll-to-roll process further avoids generation of sprue material, thus reducing material waste.
Finally, while various embodiments have been described and illustrated, the disclosure is not to be construed as being limited thereto. Various modifications can be made to the embodiments by those skilled in the art without departing from the true spirit and scope of the disclosure as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 98144652 | Dec 2009 | TW | national |
This application is related to a co-pending U.S. patent application Ser. No. 12/758,128, filed on Apr. 128, 2010, and entitled “EMBOSSING ASSEMBLY, MANUFACTURING METHOD THEREOF, AND EMBOSSING METHOD USING THE SAME”. The inventors of the co-pending application are Hsi-Chang Wu and Tai-Cherng Yu. The co-pending application has the same assignee as the present application. The Specification and Drawings of the co-pending application are incorporated herein by reference.
