Patent Publication Number: US-2012034379-A1

Title: Coating method

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to coating technology, and particularly, to a coating method for forming a metallic coating on a workpiece, the workpiece having an uncoated portion conforming to a predetermined pattern. 
     2. Description of Related Art 
     Electronic products, such as computers, cell phones, and digital cameras often display a logo or other graphic on a predetermined region of an outer surface thereof, and are coated with a film layer formed on the residual region of the outer surface. Accordingly, prior to coating the shell, a template covers the predetermined region for the graphic. The template has the same dimension and configuration as the graphic. After coating the film layer on the residual region of the outer surface, the template is removed. However, edges of the target region are unclear. As a result, precision of the graphic formed subsequently may fail to meet predetermined requirements. Thus, a coating method is desired to overcome the limitations described. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present coating method can 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 presentment coating method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the views. 
         FIG. 1  is an isometric view of a workpiece, a tape mask and a screen printing stencil employed in a method according to an embodiment of the present disclosure. 
         FIG. 2  shows the tape mask laminated onto the workpiece. 
         FIG. 3  shows applying ink onto the workpiece the tape mask. 
         FIG. 4  shows the ink being solidified on the workpiece. 
         FIG. 5  shows a metallic film layer formed on the workpiece. 
         FIG. 6  shows the resultant coated workpiece after removing the ink. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a workpiece  10 , a tape mask  20  and a screen printing stencil  30  in accordance with an exemplary embodiment. The workpiece  10  and the tape mask  20  can be glass, silicon, quartz, silicon carbide, plastic, metal, metal alloy, or stainless steel. In the present embodiment, the workpiece  10  is a plastic plate for manufacturing a shell of portable computer, and the tape mask  20  is polyimide film. The workpiece  10  includes a flat outer surface  11 . The outer surface  11  includes a coating region  121  and a pattern region  111  for forming a graphic of the portable computer. The tape mask  20  has a through hole  21  of the same dimension and configuration as the graphic. The screen printing stencil  30  includes a mesh region  31  of the same dimension and configuration as the graphic. 
     Referring to  FIGS. 1 and 2 , the tape mask  20  is laminated on the coating region  121  of the workpiece  10 . The tape mask  20  can be directly adhered on the coating region  121  in such a manner that the through hole  21  is aligned with the pattern region  111 , and the through hole  21  is gas-proof with the coating region  121 . 
     Referring to  FIGS. 1 to 4 , the screen printing stencil  31  is placed on the tape mask  20  with the mesh region  31  aligned with the through hole  21 . A scratching tool  32  is employed to spread the ink  40  over the screen printing stencil  31  and squeeze the ink  40  into the through hole  21  over the pattern region  111 . The ink  40  can be solidified by UV irradiation and easily stripped from the workpiece  10 . 
     The ink  40  is then solidified. It is understood that the solidified ink  40  has the same dimension and configuration as the through hole  21 , and entirely covers the pattern region  111 . 
     Referring to  FIGS. 3 to 5 , the tape mask  20  is removed, and a metallic film layer  50  is formed on the coating region  121  using a typical coating process, such as physical vapor deposition, chemical vapor deposition, laser assisted evaporation or ion polymerization deposition. 
     Referring to  FIGS. 5 and 6 , the solidified ink  40  is removed, thereby forming a pattern  60  on the pattern region  111 . The solidified ink  40  can be directly stripped from the workpiece  10  or dissolved with chemical agents. It is understood that the edge of the pattern  60  is consistent with the edge of the through hole  21 . Therefore, the edge of the pattern  60  is clear. 
     The embodiments described are intended to illustrate rather than limit the disclosure. Variations may be made to the embodiments and methods without departing from the spirit of the disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the disclosure.