This application claims priority of Taiwanese patent application no, 102123981, filed on Jul. 4, 2013, the entire disclosure of which is hereby incorporated by reference.
1. Field of the Invention
This invention relates to a method of depositing a metal layer on an electrically non-conductive plastic member, and to a housing for a mobile device.
2. Description of the Related Art
Currently, a mobile communication device is designed Toward volume miniaturization. In order no achieve volume miniaturization, an antenna 15 usually formed directly on a back cover of the mobile communication device.
U.S. Pat. No. 7,060,421 B2 discloses a method for producing conductor track structures on an electrically non-conductive support material. An electrically non-conductive metal compounds are insoluble spinel-based inorganic oxides and are dispersed in the support material. The conductor track structures are formed on the supporting material by depositing a metalized layer on metal nuclei produced by using electromagnetic radiation to break up the electrically non-conductive metal compounds.
Another process of forming the antenna on the back cover of the mobile communication device includes the following steps: (1) mixing copper and palladium ions with a plastic material to form a mixture, followed by injection molding the mixture to form a back cover of the mobile communication device; (2) irradiating a part of a surface of the back cover with laser to activate the copper and palladium ions; and (3) depositing a metal layer on the part of the surface of the back cover where the copper and palladium ions are activated so as to form an antenna. It should be noted that palladium ion is used as a bridge to interconnect the back cover and the metal layer.
In the aforesaid method, palladium ion, which is a relatively expensive metal, is spread throughout the whole plastic material of the back cover while the antenna is only formed on a certain part of the back cover. This results in a relatively high incurred cost in this method. Moreover, physical properties (e.g., hardness, brittleness, elasticity, etc.) of the plastic material dispersed with copper and palladium ions are changed, and thus, the quality of the back cover might not be able to meet all requirements in the industry. Furthermore, the abovementioned process is only suitable for certain kinds of plastic materials.
Therefore, the object of the present invention is to provide a method of depositing a metal layer on an electrically non-conductive plastic member, and a housing for a mobile device, that can overcome at least one of the aforesaid drawbacks of the prior art.
According to one aspect of this invention, a method of depositing a metal layer on an electrically non-conductive plastic member comprises the following steps:
(a) mixing a plastic material and a laser-sensitive additive to form a mixture, followed by injection molding the mixture to form an electrically non-conductive plastic member that has a surface;
(b) irradiating a part of the surface of the electrically non-conductive plastic member with laser to engrave the electrically non-conductive plastic member so as to form a roughened region in the electrically non-conductive plastic member;
(c) forming an activating layer on the roughened region of the electrically non-conductive plastic member for metalizing the roughened region in the electrically non-conductive plastic member; and
(d) forming a metal layer on the activating layer on the roughened region of the electrically non-conductive plastic member.
According to another aspect of the invention, there is provided a housing for a mobile device, which is made by the abovementioned method of this invention.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment of this invention, with reference to the accompanying drawings, in which:
Referring to
(a) mixing a plastic. ma serial and a laser-sensitive additive 2 to form a mixture, followed by injection molding the mixture to form an electrically non-conductive plastic member 100 that has a surface 101 (see
(b) irradiating the irradiating area 11 of the surface 101 of the electrically non-conductive plastic member 100 with laser to engrave the electrically non-conductive plastic member 100 so as to form a roughened region 13 in the electrically non-conductive plastic member 100 (see
(c) forming an activating layer 4 on the roughened region 13 of the electrically non-conductive plastic member 100 for metalizing the roughened region 13 in the electrically non-conductive plastic member 100 (see
(d) forming a metal layer 5 on the activating layer on the roughened region 13 of the electrically non-conductive plastic member 100 (see
Referring to
Referring to
The roughened region 13 with the indentations 14 may improve the bonding strength of an alloy layer subsequently formed thereon.
Referring to
Alternatively, in step (c), the activating layer 4 can be formed by directly immersing the electrically non-conductive plastic member 100 in an activating liquid containing palladium nano-particle. For example, the activating liquid may contain palladium sulfide or palladium chloride so as to provide palladium nano-particle. The activating liquid is chosen based on the plastic materials used in step (a). Since formation of the palladium activating layer 4 is well known to a skilled artisan, a detailed description thereof is omitted herein for the sake of brevity. A publication with relevant information is “Studying Pd nanoparticles as activator application for electroless copper deposition” (C. C. Tseng, Y. C. Chen, C. P. Chang, J. L. Kuo and M. D. Ger; Journal of C.C.I.T.; Vol. 40; NO. 1; May, 2011).
Referring to
Referring to
To sum up, by virtue of the laser-sensitive additive 2, the roughened region 13 of the electrically non-conductive plastic member 100 could be formed and the activating layer 4 may be formed only in the roughened region 13, so that production costs could be effectively reduced. Moreover, since the activating layer 4 is only formed on a part of the surface of the electrically non-conductive plastic member 100, the effect of the activating layer 4 on the physical properties (e.g., hardness, brittleness, and elasticity) of the electrically non-conductive plastic member 100 could be minimized. Furthermore, the method of depositing a metal layer 5 on an electrically non-conductive plastic member 100 according to the present invention is suitable for various kinds of plastic materials.
While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation and equivalent arrangements.
Number | Date | Country | Kind |
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102123981 | Jul 2013 | TW | national |