Patent Publication Number: US-2013230276-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 
     Many OPCBs use rigid substrates. During manufacturing process, one rigid substrate needs to be assembled on an apparatus for manufacturing the OPCBs, then the formed OPCB needs to be taken off the apparatus, and another rigid substrate needs to be placed on the apparatus, and so on, 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 will 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 cross-sectional view of an OPCB, according to a first embodiment. 
         FIG. 2  is a schematic view of an apparatus for manufacturing the OPCB of  FIG. 1 , according to a second embodiment. 
         FIG. 3  is a flowchart of a method for manufacturing the OPCB of  FIG. 1 , according to a third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an optical printed circuit board (OPCB)  100  in accordance with a first embodiment. The OPCB  100  includes a flexible first substrate  10 , a first cladding layer  20 , a core layer  30 , a second cladding layer  40 , and a flexible second substrate  50 . 
     The first cladding layer  20  is formed on the first substrate  10 . The core layer  30  is formed on the first cladding layer  20  so as to define an optical waveguide pattern  30   a . The second cladding layer  40  is formed on the core layer  30 . The second substrate  50  is formed on the second cladding layer  40 . 
     The first substrate  10  and the second substrate  50  protect the first cladding layer  20  and the second cladding layer  40  respectively. In this embodiment, the first substrate  10  and the second substrate  50  are made of polyethylene terephthalate (PET). In another embodiment, the first substrate  10  and the second substrate  50  can be made of polyethersulfone (PES) or other flexible transparent material. 
     The first cladding layer  20  and the second cladding layer  40  protect the core layer  30  and allow optical signals to be transmitted only along the core layer  30 . The first cladding layer  20  and the second cladding layer  40  are made of low refractive material, such as the following materials without light sensitive groups: polyacrylate, polysiloxane, polyimide, polycarbonate, fluorinated polymer, or mixture of at least two above materials. In this embodiment, the material of the first cladding layer  20  is substantially the same as the material of the second cladding layer  40 . In other embodiments, the material of the first cladding layer  20  can be different from the material of the second cladding layer  40 . 
     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 high refractive index material, such as the following materials with light sensitive groups: polyacrylate, polysiloxane, polyimide, polycarbonate, fluorinated polymer, or mixture of at least two above materials. 
     Referring to  FIG. 2 , an apparatus  200  for manufacturing the OPCB of  FIG. 1 , according to a second embodiment, includes a working platform  210 , a first releasing reel  221 , and a film take-up reel  222 . The apparatus  200  further includes a first roller pressing device  230 , a second roller pressing device  240 , a third roller pressing device  250 , and a fourth roller pressing device  270  on a top of the working platform  210  and arranged one after the other along the direction of movement of the first substrate  10 . 
     The first releasing reel  221  and the film take-up reel  222  are arranged at two ends of the working platform  210 . The first releasing reel  221  is used for paying out the first substrate  10 , and the film take-up reel  222  is used for taking up the formed OPCB  100 . The first roller pressing device  210  is used for forming the first cladding layer  20  on the substrate  10 . The second roller pressing device  220  is used for forming the core layer  30  on the first cladding layer  20 . The third roller pressing device  230  is used for forming the second cladding layer  40  on the core layer  30 . The fourth roller pressing device  240  is used for pressing the second substrate  50  on the second cladding layer  40 . 
     The first roller pressing device  230  includes a first feeder  231 , a first pressing roller  232 , and a first drying element  233 . The first pressing roller  232  is a copper-coated roller and has a smooth rolling surface. The first feeder  231  is arranged between the releasing reel  221  and the first pressing roller  232  and is used for feeding a first cladding layer forming solvent to the substrate  10 . The first cladding layer forming solvent is a solvent for forming the first cladding layer  20 . The first pressing roller  232  and the working platform  210  cooperate to press the first cladding layer forming solvent on the substrate  10  to obtain a first cladding solvent layer. The first cladding solvent layer is a layer of the first cladding layer forming solvent. The first drying device  233  is arranged after the first pressing roller  232  and is used for drying the first cladding solvent layer to obtain the first cladding layer  20 . In this embodiment, the first drying element  233  is an ultraviolet source. 
     The second roller pressing device  240  includes a second feeder  241 , a second pressing roller  242 , and a second drying element  243 . The second pressing roller  242  is a copper-coated roller and has a rolling surface defining impression patterns coupled with the optical waveguide pattern. The second feeder  241  is arranged between the first roller pressing device  230  and the second pressing roller  242  and feeds a core layer forming solvent to the substrate  10 . The core layer forming solvent is a solvent for forming the core layer  30 . The second pressing roller  242  and the working platform  10  cooperate to press the core layer forming solvent on the first cladding layer  20  to obtain a core solvent layer. The core solvent layer is a layer of the core layer forming solvent. The first drying device  243  is arranged after the second pressing roller  242  and dries the core solvent layer to obtain the core layer  30 . In this embodiment, the second drying element  243  is an ultraviolet source. 
     The third roller pressing device  250  includes a third feeder  251 , a third pressing roller  252 , and a third drying element  253 . The third pressing roller  252  is a copper-coated roller and has a smooth rolling surface. The third feeder  253  is arranged between the second roller pressing device  240  and the third pressing roller  252  and is used for feeding a second cladding layer forming solvent to the core layer  30 . The second cladding layer forming solvent is a solvent for forming the second cladding layer  40 . The third pressing roller  252  and the working platform  10  cooperate to press the third cladding layer forming solvent on the core layer  30  to obtain a second cladding solvent layer  40 . The second cladding solvent layer is a layer of the second cladding layer forming solvent. The third drying device  253  is arranged after the third pressing roller  252  and is used for drying the second cladding solvent layer to obtain the second cladding layer  40 . In this embodiment, the second drying element  253  is an ultraviolet source. 
     The fourth roller pressing device  270  includes a fourth pressing roller  271  and a second releasing reel  272 . One end of the second substrate  50  is wound around the second releasing reel  272 , and the other end of the second substrate  50  is pressed on the second cladding layer  40  by the fourth pressing roller  271 . 
     Referring to  FIG. 3 , a method for manufacturing the OPCB  100  using the apparatus  200 , according to a third embodiment, includes the following steps. 
     In step S 1 , the flexible first substrate  10  is cleaned and then rolled out from the first releasing reel  221 . In particular, one end of the first substrate  10  is wound around the first releasing reel  221 , and the other end of the first substrate  10  is fixed on the film take-up reel  222 . The first releasing reel  221  and the film take-up reel  222  are spaced at a predetermined distance from each other. The first substrate  10  is released on the working platform  210 . A moving direction of the first substrate  10  is substantially parallel to a length direction of the working platform  210 . The first substrate  10  is cleaned to improve the adhesive potential of the first cladding layer  20  on the first substrate  10 . 
     In step S 2 , a first cladding layer  20  is formed on the first substrate  10  using the first roller pressing device  230 . In this embodiment, the first feeder  231  feeds the first cladding layer forming solvent to the first substrate  10 . The first substrate  10  passes through a channel between the first pressing roller  232  and the working platform  210 . The first pressing roller  232  presses the first cladding layer forming solvent on the first substrate  10  to obtain the first cladding solvent layer. The first drying element  233  solidifies the first cladding solvent layer to form the first cladding layer  20 . 
     In step S 3 , a core layer  30  is formed on the first cladding layer  20  using the second roller pressing device  240 . In this embodiment, the second feeder  241  feeds the core layer forming solvent to the first cladding layer  20 . The first substrate  10  with the first cladding layer  20  passes through a channel between the second pressing roller  241  and the working platform  210 , the second pressing roller  242  presses the core layer forming solvent on the first cladding layer  20  to obtain the core solvent layer. The second drying device  243  solidifies the core solvent layer to obtain the core layer  30 . 
     In step S 4 , a second cladding layer  40  is formed on the core layer  30  using the third roller pressing device  250 . In this embodiment, the third feeder  251  feeds the second cladding layer forming solvent to the core layer  30 . The first substrate  10  with the first cladding layer  20  and the core layer  30  passes through a channel between the third pressing roller  252  and the working platform  210 . The third pressing roller  252  presses the second cladding layer forming solvent on the core layer  30  to form the second cladding solvent layer. The third drying device  253  solidifies the second cladding solvent layer to form the second cladding layer  40 . 
     In step S 5 , a flexible second substrate  50  is formed on the second cladding layer  40  to obtain the OPCB  100  using the fourth roller pressing device  270 . In this embodiment, the second release reel  272  pays out the second substrate  50  onto the second cladding layer  40 . The first substrate  10  with the first cladding layer  20 , the core layer  30 , and the second cladding layer  40  passes through a channel between the fourth pressing roller  271  and the working platform  210 . The fourth pressing roller  271  presses the second substrate  50  on the second cladding layer  40 . 
     In step S 6 , the film take-up reel  222  takes up the formed OPCB  100 . 
     In step S 7 , the formed OPCB  100  is cut to a predetermined size as required. In this embodiment, a laser cuts the formed OPCB  100 . 
     By employing the apparatus and the method, the OPCB  100  can be produced in any size required, and the manufacturing efficiency of the OPCB  100  is improved. 
     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.