Patent Publication Number: US-2010108343-A1

Title: Housing and manufacturing method thereof

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a housing and a manufacturing method thereof. 
     2. Description of Related Art 
     Housings of portable electronic devices are commonly made of plastic or metal. These housings are usually subjected to a surface treatment to form colorful or protective coatings thereon. The surface treatment method may be spray painting, electrophoretic depositing, or vacuum depositing. The coating formed by vacuum depositing can present attractive metallic appearance. Therefore, the vacuum depositing method is widely used. However, the coating formed by vacuum depositing method now can only present a single color. Furthermore, the coating cannot present different colors at a different observing direction. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURE 
       Many aspects of the housing can be better understood with reference to the following figure. The components in the figure are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the housing. Moreover, in the drawing like reference numerals designate corresponding parts throughout the several views. 
       The FIGURE is a cross-sectional view of a present embodiment of a housing. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the FIGURE, in an exemplary embodiment, a housing  10  includes a substrate  11 , a base paint coating  13  formed on one surface of the substrate  11 , a vacuum depositing coating  15  formed on the base paint coating  13 , and a top paint coating  17  formed on the vacuum depositing coating  15 . 
     The substrate  11  may be made of plastic selected from a group consisting of polyethylene (PE), polyamide (PA), polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), and polyethylene terephthalate (PET). Alternatively, the substrate  11  may be made of metal. 
     The base paint coating  13  is an ultraviolet curing paint coating. The ultraviolet curing paint may be polyurethane acrylate paint. The ultraviolet curing paint may contain polyurethane acrylate pre-polymer, ultraviolet initiation agent(s), and additive agent(s). The base paint coating  13  has a smooth and glossy surface. The base paint coating  13  has a mirror reflection to light. 
     The vacuum depositing coating  15  is formed by vacuum depositing method. The vacuum depositing coating  15  may include a first metal coating  151 , a second metal coating  153 , and a third metal coating  155 . 
     The first metal coating  151  is directly formed on the base paint coating  13 . The first metal coating  151  may be an aluminum coating. The light transmittance of the first metal coating is about 25-35%, preferably, 30%. 
     The second metal coating  153  is formed on the first metal coating  151 . The second metal coating  153  may be a silicon dioxide coating. The thickness of the second metal coating  153  is about 150-450 nm. The second metal coating  153  can present different colors at a different thickness in a range of about 150-450 nm. 
     The third metal coating  155  is formed on the second metal coating  153 . The third metal coating  155  may be a titanium coating. The light transmittance of the third metal coating is about 45-55%, preferably, 50%. 
     The combination of the first metal coating  151 , the second metal coating  153 , and the third metal coating  155  can achieve different refractions and reflections to light at different observing directions by using the above-mentioned materials, light transmittance and thickness of the three metal coatings, thus makes the vacuum depositing coating  15  present different colors at different observing directions to obtain a more attractive housing  10 . The base paint coating  13  can mirror reflect light, by which the gloss of the vacuum depositing coating  15  is enhanced. 
     It should be understood, the vacuum depositing coating  15  can also be directly formed on the substrate  11 , i.e., the first metal coating  151  is directly formed on the substrate  11 . 
     The top paint coating  17  is transparent. The paint used in the top paint coating  17  may be ultraviolet curing paint, polyurethane paint or unsaturated polyester paint. In this embodiment, ultraviolet curing paint is the preferred paint for the top paint coating  17 . The top paint coating  17  has a high rigidity and can protect the vacuum depositing coating  15  from abrasion or scratch. 
     A method for making the housing  10  may comprise the following steps: providing a substrate; vacuum depositing a first metal coating using aluminum on one surface of the substrate, the first metal coating having a light transmittance of about 25-35%; vacuum depositing a second metal coating using silicon dioxide on the first metal coating, the second metal coating having a thickness of about 150-450 nm; vacuum depositing a third metal coating using titanium on the second metal coating, the third metal coating having a light transmittance of about 45-55%. Each step is described in more detail below. 
     A substrate  11  is provided. The substrate  11  may be made of plastic selected from a group consisting of polyethylene (PE), polyamide (PA), polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), and polyethylene terephthalate (PET). Alternatively, the substrate  11  may be made of metal. 
     A base paint coating  13  is applied on one surface of the substrate  11 . The base paint coating  13  is an ultraviolet curing paint coating. The ultraviolet curing paint may be polyurethane acrylate paint. The ultraviolet curing paint may contain polyurethane acrylate pre-polymer, ultraviolet initiation agent(s), and additive agent(s). 
     A vacuum depositing coating  15  is applied on the base paint coating  13  by vacuum depositing method. Forming the vacuum depositing coating  15  may include the steps of forming the first metal coating  151 , the second metal coating  153 , and the third metal coating  155 . 
     An aluminum coating is vacuum deposited onto the base paint coating  13  to form the first metal coating  151 . The light transmittance of the first metal coating  151  is about 25-35%, preferably, 30%. 
     A silicon dioxide coating is vacuum deposited onto the first metal coating  151  to form the second metal coating  153 . The thickness of the second metal coating  153  is about 150-450 nm. The second metal coating  153  can present different colors at a different thickness in a range of about 150-450 nm. 
     A titanium coating is vacuum deposited onto the second metal coating  153  to form the third metal coating  155 . The light transmittance of the third metal coating  155  is about 45-55%, preferably, 50%. 
     A top paint coating  17  is applied on the third metal coating  155  by spray painting. The paint used in forming the top paint coating  17  may be ultraviolet curing paint, polyurethane paint or unsaturated polyester paint. In this embodiment, ultraviolet curing paint is the preferred paint for the paint coating  17 . The top paint coating  17  has a high rigidity and can protect the vacuum depositing coating  15  from abrasion or scratch. 
     It should be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.