Patent Publication Number: US-2013230275-A1

Title: Optical printed circuit board, apparatus and method for manufacturing same

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to an optical printed circuit board (OPCB), an apparatus and a method for manufacturing the OPCB. 
     2. Description of Related Art 
     OPCBs include core layers for transmitting optical signals. The core layers define optical waveguide patterns. In related art, the optical waveguide patterns are formed using yellow light photolithograph method. However, the yellow light photolithograph method needs much time, which will reduce the manufacturing efficiency of the OPCBs. 
     Therefore, it is desirable to provide an OPCB, an apparatus and a method for manufacturing the OPCB that can overcome the above-mentioned limitations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the embodiments should be better understood with reference to the following drawings. 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 the several views. 
         FIG. 1  is a schematic view of an OPCB, according to a first exemplary embodiment. 
         FIG. 2  is schematic view of an apparatus for manufacturing the OPCB of  FIG. 1 , according to a second exemplary embodiment. 
         FIG. 3  is a flow chart of a method for manufacturing the OPCB of  FIG. 1 , according to a third exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an optical printed circuit board (OPCB)  100  in accordance with a first exemplary embodiment. The OPCB  100  includes a rigid substrate  10  having a loading surface  101 , a first cladding layer  20  formed on the loading surface  101  of the substrate  10 , a core layer  30  formed on the first cladding layer  20 , and a second cladding layer  40  formed on the core layer  30 . The core layer  30  defines an optical waveguide pattern  30   a.    
     The substrate  10  is substantially cuboid and has a circuit layer (not shown). The circuit layer may be made of metal material or conductive compound. The metal material may be gold, silver, or copper. The conductive compound may be indium tin oxide (ITO). 
     The refractive index of the core layer  30  is greater than the refractive index of the first cladding layer  20  and the refractive index of the second cladding layer  40 . The core layer  30  is made of a high refractive index material, such as the following materials with light-sensitive groups: polyacrylate, polysiloxane, polyimide, polycarbonate, fluorinated polymer, or mixture of the above materials. 
     The first cladding layer  20  and the second cladding layer  40  are made of a low refractive index material, such as the following materials without light-sensitive groups: polyacrylate, polysiloxane, polyimide, polycarbonate, fluorinated polymer, or mixture of the above materials. 
     In this embodiment, the material of the second cladding layer  40  is the same as the material of the first cladding layer  20 . In other embodiments, the material of the second cladding layer  40  can be different from the material of the first cladding layer  20 . 
     Referring to  FIG. 2 , an apparatus for manufacturing the OPCB  200 , according to a second exemplary embodiment, includes a first pressing device  210 , a second pressing device  220 , and a third pressing device  230 . 
     The first pressing device  210  includes a first pressing roller  211 , a first auxiliary roller  212 , a first feeder  213 , and a first drying element  218 . The first pressing roller  211  has a smooth first circumferential surface. The first pressing roller  211  is above the first auxiliary roller  212 , and is spaced at a predetermined distance from the first auxiliary roller  212 , and thus forms a molding channel  214  therebetween. 
     The molding channel  214  includes an inlet  215  and an outlet  216 . The first feeder  213 , the first drying element  218 , and the first pressing roller  211  are positioned on a first side of the molding channel  214 . The first auxiliary roller  212  is positioned on a second side of the molding channel  214  opposite to the first side. The first pressing roller  211  is positioned between the first feeder  213  and the first drying element  218 . The first feeder  213  is used for providing a first cladding layer forming a solvent. The first pressing roller  211  and the first auxiliary roller  212  are rotated in opposite directions, and press the first cladding layer forming a solvent on the loading surface  101  to form a first cladding solvent layer. The first pressing roller  211  and the first auxiliary roller  212  also cooperatively transfer the substrate  10  from the inlet  215  to the outlet  216 . The drying element  218  is used for solidifying the first cladding solvent layer to obtain the first cladding layer  20 . In this embodiment, the first pressing roller  211  is rotated clockwise, and the first auxiliary roller  212  is rotated counterclockwise. 
     The second pressing device  220  is used for forming a core layer  30  with optical waveguide patterns on the first cladding layer  20 . The second pressing device  220  is different from the first pressing device  210  and includes a second pressing roller  221 , a second auxiliary roller  222 , a second feeder  223 , and a second drying element  228  in that order as the substrate  10  moves along. The second feeder  223  is used for providing a core layer forming solvent. The substrate  10  with the first cladding layer  20  passes through a channel between the second pressing roller  221  and the second auxiliary roller  222 , and thus the core layer forming solvent is pressed on the first cladding layer  20  to obtain a core layer solvent layer. The second drying element  228  is used for drying the core layer solvent layer to obtain the core layer  30 . The difference between the first pressing device  210  and the second pressing device  220  is that the second pressing roller  221  has a second circumferential surface with impression patterns coupled with the optical waveguide patterns. 
     The third pressing device  230  is used for forming a second cladding layer  40  on the core layer  30 . The structure of the third pressing device  230  is the same as the structure of the first pressing device  210  and includes a third pressing roller  231 , a third auxiliary roller  232 , a third feeder  233 , and a third drying element  238  in that order as the substrate  10  moves along. The third pressing roller  231  has a smooth third circumferential surface. The third feeder  233  is used for providing a second cladding forming solvent. The substrate  10  with the first cladding layer  20  and the core layer  30  passes through a channel between the third pressing roller  231  and the third auxiliary roller  232 , and thus the second cladding layer forming solvent is pressed on the core layer  30  to obtain a second cladding solvent layer. The third drying element  238  is used for solidifying the second cladding solvent layer to form the second cladding layer  40 . 
     The direction of movement of the substrate  10  is substantially the same as the lengthwise direction of the substrate  10 . The distance between the first pressing roller  211  and the second pressing roller  221  and the distance between the second pressing roller  221  and the third pressing roller  231  are both less than the length of the substrate  10 . The first pressing roller  211 , the second pressing roller  221 , and the third pressing roller  231  are at a same height with respect to a horizontal surface, and the first auxiliary roller  212 , the second auxiliary roller  222 , and the third auxiliary roller  232  are at the same height with respect to the same horizontal surface. Therefore, the substrate  10  can move from the first pressing device  210  to the second pressing device  220 , and then automatically enter the third pressing device  230 . In this embodiment, the distance between the first pressing roller  211  and the second pressing roller  221  is substantially equal to the distance between the second pressing roller  221  and the third pressing roller  231 . 
     In this embodiment, the first drying element  218 , the second drying element  228 , and the third drying element  238  are ultraviolet (UV) sources. 
     Each of the first auxiliary roller  212 , the second auxiliary roller  222 , and the third auxiliary roller  232  has a smooth outer circumferential surface. 
     The roller pressing apparatus  200  also can be used for manufacturing other elements. The outer circumferential surfaces of the first to third auxiliary rollers  212 ,  222 ,  232  and the first to third pressing rollers  211 ,  221 ,  231  can be designed or redesigned according to a user&#39;s requirement. 
     Referring to  FIG. 3 , a method for manufacturing the OPCB  100  using the apparatus  200 , according to a third exemplary embodiment, is shown. The method includes the following steps. 
     In step S 1 : the rigid substrate  10  having a loading surface  101  is provided, and the loading surface  101  is cleaned. 
     In step S 2 , the first cladding layer  210  is formed on the substrate  10  using the first pressing device  210 . In particular, the substrate  10  is positioned on the inlet  215 , and the loading surface  101  faces the first feeder  213 . The first feeder  213  provides the first cladding layer forming a solvent to the loading surface  101 , the first pressing roller  211  and the first auxiliary roller  212  rotate to press the first cladding layer forming a solvent on the loading surface  101  to form a first cladding solvent layer, then the first drying device  218  solidifies the first cladding solvent layer to obtain the first cladding layer  20 . 
     In step S 3 , the substrate  10  with the first cladding layer  20  directly enters the second roller pressing device  220 , and the core layer  30  with optical waveguide patterns is formed on the first cladding layer  20  using the second roller pressing device  220 . In particular, the second feeder  223  provides a core layer forming solvent to the first cladding layer  20 . The second pressing roller  221  and the second auxiliary roller  222  cooperatively press the core layer forming solvent on the first cladding layer  20  to obtain the core layer solvent layer  30 . The second drying element  228  solidifies the core solvent layer to obtain the core layer  30  with optical waveguide patterns. 
     In step S 4 , the substrate  10  with the first cladding layer  20  and the core layer  30  directly enters the third roller pressing device  230 , and the second cladding layer  40  is formed on the core layer  30  using the third roller pressing device  230 . In particular, the third feeder  238  provides a second cladding forming a solvent to the core layer  30 . The third pressing roller  231  and the second auxiliary roller  232  cooperate to press the second cladding forming solvent on the core layer  30  to obtain the second cladding solvent layer. The third drying element  238  solidifies the second cladding solvent layer to obtain the second cladding layer  40 . 
     By employing the first to third roller pressing devices  210 ,  220 ,  230 , the optical waveguide patterns can be directly formed on the core layer  30 , and thus the manufacturing efficiency is greatly improved. At the same time, the first to third roller pressing devices  210 ,  220 ,  230  will not produce chemical waste, and thus represent no threat to the environment. 
     It will be understood that the above particular embodiments and methods 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.