Patent Publication Number: US-2012034381-A1

Title: Method for forming a patterned coating

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to surface coating technology, and particularly, to a coating method for forming a patterned film layer on an outer surface of a workpiece. 
     2. Description of Related Art 
     Often graphics, such as logos, are formed on electronic products, such as computers, cell phones, and digital cameras by masking. However, edges of the masked regions may not be sharp because the liquid masking material used may seep under the edges of the masking material. Thus, a coating method is desired to overcome the limitations described. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present 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 method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the views. 
         FIG. 1  is an isometric view of a workpiece, a masking fixture provided in an embodiment of the present disclosure, the workpiece includes a coating region and a pattern region, the masking fixture includes a liquid masking applicator having a groove and a workpiece holders pivotably connected to the liquid masking applicator. 
         FIG. 2  shows the groove filled with liquid masking material. 
         FIG. 3  shows the workpiece holder pivoted to the liquid masking applicator. 
         FIG. 4  shows the ink after being solidified. 
         FIG. 5  shows a film layer formed on the workpiece. 
         FIG. 6  shows the workpiece after removing the masking material. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a masking fixture  10  and a workpiece  20  provided in accordance with an exemplary embodiment. The workpiece  20  can be glass, silicon, quartz, carborundum, plastic or stainless steel. In the present embodiment, the workpiece  20  is a plastic plate used as part of an encasing for portable computer. The workpiece  20  includes an outer surface  21 . The outer surface  21  includes a flat coating region  211  and a flat pattern region  221  for forming a graphic. In the present embodiment, as shown with dashed line in  FIG. 1 , the pattern region  221  is ring-shaped. The workpiece  20  is detachably fixed in the masking fixture  10 . 
     The masking fixture  10  includes a liquid masking applicator  11  and a workpiece holder  12  pivotably connected to the liquid masking applicator  11 . The liquid masking applicator  11  has a masking surface  111 . A groove  112  having the same outline shape as the pattern region  221  is defined in the masking surface  111 . The liquid masking applicator  11  is resilient, and is capable of deforming along a direction parallel to its height direction under a pressure and recovering its original shape when the pressure is released. The liquid masking applicator  11  can be made of shape memory alloy or shape memory polymer. For example, the liquid masking applicator  11  can be selected from a group consisting of titanium-nickel alloy, titanium-nickel-aluminium alloy, titanium-nickel-aluminium-zinc alloy, titanium-nickel-aluminum-zinc-copper alloy, copper-zinc-aluminium alloy, copper-zinc-calcium alloy, copper-aluminium-nickel alloy, copper-aluminium-boron alloy, and copper-zinc-silicon alloy, polyvinyl acetate based polymer, and polyurethane based polymer. The workpiece holder  12  includes a parting surface  121 . An accommodating cavity  122  for accommodating the masking fixture  21  is defined in the parting surface  121 . The accommodating cavity  122  has the same outline shape as the masking fixture  21 . When the workpiece holder  12  is pivotably laminated on the liquid masking applicator  11 , the pattern region  221  is superposed on the groove  112 , and the groove  112  is gas-proof with the coating region  211 . 
     Referring to  FIGS. 1 to 2 , the groove  112  is filled with liquid masking material  30  using a typical ink injection process, a screen scratching process, or ink spraying process. In the present embodiment, the liquid masking material  30  is ink, and can be solidified by UV irradiation and easily stripped from the workpiece  20 . 
     Referring to  FIGS. 1 to 4 , the workpiece holder  12  is rotated onto the liquid masking applicator  11 , and a pressure is downwardly applied on the workpiece holder  12 . It is understood that the pattern region  221  is superposed on the liquid masking material  30  in the groove  112 , and the liquid masking applicator  11  resiliently abuts against the workpiece  20  and deforms downwardly. As a result, a portion of the ink  30   a  adheres to and coats the pattern region  221 . 
     Referring to  FIGS. 1 to 4 , the workpiece holder  12  containing the workpiece  20  is quickly removed from the liquid masking applicator  11 , and the ink  30   a  is then solidified. It is understood that the solidified ink  30   a  has the same dimension and configuration as the groove  112 , and entirely covers the pattern region  221 . 
     Referring to  FIGS. 1 to 5 , a film layer  40  is formed on the coating region  211  using a typical coating process, such as physical vapor deposition, chemical vapor deposition, laser assisted evaporation or ion polymerization deposition. 
     Referring to  FIGS. 1 ,  5  and  6 , the solidified ink  30   a  is removed, thereby forming a pattern  60  on the pattern region  221 . The solidified ink  30   a  can be directly stripped from the workpiece  20  or dissolved with chemical agents. It is understood that the edge of the pattern  60  is consistent with the edge of the groove  112 . 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.