Patent Application
20140302233
1. Technical Field
The present disclosure relates to molding devices, and particularly to a molding roller and a method of manufacturing the molding roller.
2. Description of Related Art
Molding rollers generally include a roller body and a copper layer coated on an outer cylindrical surface of the roller body. A micro-structure pattern is formed on the copper layer for molding an optical element, such as a brightness enhancement film. However, when a part of the micro-structure pattern of the copper layer is damaged, the entire copper needs to be replaced, which increases a cost of the molding roller.
Therefore, it is desirable to provide a molding roller and a method of manufacturing the molding roller to overcome the limitations described.
Embodiments of the disclosure will be described with reference to the drawings.
The roller body 11 is substantially cylindrical and includes a cylindrical surface 110. The roller body 11 is made of metal, such as copper, and a Mohs hardness of the roller body 11 is greater than about 2.5. In the embodiment, in order to improve an adhesive force of the cylindrical surface 110, the cylindrical surface 110 is roughened by a roughing process.
The molding film 12 is spray-coated onto the cylindrical surface 110 and forms an annular tube sleeved on the roller body 11. The molding film 12 includes a molding surface 120 facing away from the cylindrical surface 110. A micro-structure pattern 121 is formed on the molding surface 120 to mold the optical element. The molding film 12 is made of flexible polymer material including polydimethylsiloxane (PDMS) and a number of silicon dioxide (SiO2) nano-particles permeated in a network structure of the PDMS. The chemical formula of PDMS is CH3[Si(CH3)2O]nSi(CH3)3, where “n” is the number of repeating [Si(CH3)2O] monomer units. The PDMS has a good bonding resistance with a resin of the optical element, which makes the molding film 12 easily separate from the optical element. The SiO2 nano-particles improve a strength and an abrasion resistance of the molding film 12. The SiO2 nano-particles grow in the network structure of the PDMS via a sol-gel method. A diameter of the SiO2 nano-particles is from about 1 nm to about 100 nm.
In the embodiment, a thickness of the molding film 12 is substantially uniform. The molding film 12 is formed on the entire cylindrical surface 110. A length of the molding film 12 is substantially equal to a length of the roller body 11. The micro-structure pattern 121 includes a number of recesses defined in the molding surface 120.
S101: a PDMS solution 21 is provided. The PDMS solution 21 is made by mixing the PDMS with a curing agent in a proportion of about 10:1 to about 15:1. The PDMS and the curing agent are mixed uniformly in a receiver 20, and the PDMS is hardened by the curing agent to form the network structure. If bubbles are formed during the process of mixing, the PDMS solution 21 must be deaerated by a vacuum deaeration process. The curing agent is an ethylenediamine.
S102: the PDMS solution 21 is sprayed onto the cylindrical surface 110 of the roller body 11 by a spraying device 22 to form the molding film 12. As the roller body 11 rotates, the PDMS solution 21 is sprayed on the entire cylindrical surface 110, thereby forming the molding film 12 on the roller body 11. The thickness of the molding film 12 is substantially uniform, and the thickness can be controlled by adjusting a rotation speed of the roller body 11 and by adjusting a spraying quantity of the spraying device 22.
In order to improve adhesiveness between the roller body 11 and the molding film 12, the cylindrical surface 110 is roughened by sandblasting before the molding film 12 is formed on the roller body 11.
S103: a metal roller 24 having a transfer printing pattern 241 is provided. The metal roller 24 is rolled once over the roller body 11 to form a micro-structure pattern 121 on the molding film 12. A pressure of the metal roller 40 applied on the molding film 12 is constant.
S104: the micro-structure pattern 121 of the molding roller 10 is solidified by placing the molding roller 10 in an oven having a temperature of about 25 degrees Celsius (° C.) to about 100° C.. In the embodiment, the temperature of the oven is about 65.
S105: the solidified molding roller 10 is submerged in an additive 25 for a preset time duration, such as ten minutes. The molding roller 10 swells up from absorbing the additive 25, and the additive 25 permeates the network structure of the molding film 12. The additive 25 is a siloxane liquid and includes tetraethoxysilane (TEOS).
S106: the swelled molding roller 10 is placed in a container 28 containing a container of deionized water 26 and a container of a weak alkaline catalyst 27. The deionized water 26 and the weak alkaline catalyst 27 are vaporized when the temperature of the container 28 is increased. The vaporized deionized water 26 and the vaporized weak alkaline catalyst 27 permeate into the network structure of the molding film 12. The additive 25 is hydrolyzed and condensed by the vaporized deionized water 26 and the vaporized weak alkaline catalyst 27. A reactant is a number of SiO2 nano-particles permeated in the network structure of the PDMS.
In the embodiment, the deionized water 26 and the weak alkaline catalyst 27 increase a reaction speed of the reaction between the additive 25 and the number of SiO2 nano-particles. In other embodiments, the deionized water 26 and the weak alkaline catalyst 27 can be omitted to reduce a cost of manufacturing. A Young's modulus of the molding film 12 can be adjusted by adjusting a reaction time of the additive 25. The weak alkaline catalyst 27 is a 95% 2-amino-2-methyl-propanol solution (AMP-95). A volume ratio between the weak alkaline catalyst 27 and the deionized water 26 is about 1:5.
In the embodiment, the residual additive 25 adhered on the molding film 12 is cleaned off by a nitrogen gun (not shown).
In the embodiment, since the micro-structure pattern 121 is transferred onto the molding film 12 sprayed onto the roller body 11, a manufacturing process of the molding roller 10 is simplified.
Particular embodiments are shown and described by way of illustration only. The principles and the features of the present disclosure may be employed in various and numerous embodiments thereof without departing from the scope of the disclosure as claimed. The above-described embodiments illustrate the scope of the disclosure but do not restrict the scope of the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102112077 | Apr 2013 | TW | national |
