1. Field of the Invention
The present invention relates generally to a portable terminal, and more particularly, to a portable terminal provided with a wireless charging module.
2. Description of the Related Art
Portable terminals, such as a cellular phone and a smart phone, continue to grow in terms of functions as multimedia services are expanded. In addition, as various application programs are provided, user interface environments are developed for user convenience and to satisfy various user preferences.
Portable terminals generally include bar-type, folder-type, sliding-type, and swing-type terminals. When mobile communications such as voice and short message transmissions were principal functions, folder-type and slider-type terminals were predominant in the market. However, enlarged display devices of portable terminals have increased as multimedia services have progressed. Accordingly, physical keypads have generally been replaced by a touch screen function, which improves the portability of a portable terminal since a display device may be enlarged and the portable terminal thickness may be reduced.
In addition, a portable terminal is provided with antenna devices that enable communication in various frequency bands such as a DMB (Digital Multimedia Broadcasting), a LAN (Local Area Network), an NFC (Near Field Communication), and a Bluetooth® antenna in addition to an antenna device for a wireless communication function. Recently, portable terminals have been equipped with an antenna and a module that provides a mobile charging function.
FIG. 1 illustrates a portable terminal 100. In particular, FIG. 1 illustrates a configuration provided with a wireless charging module that includes a receiving-side resonant antenna 131 providing a wireless charging function and a receiving circuit unit provided on a substrate 133.
As illustrated in FIG. 1, the terminal 100 includes a battery-mounting groove 119 formed on a back surface of a body 101, and a camera module 117 provided at a side of the battery-mounting groove 119. The battery-mounting groove 119 is concealed by a cover member 102 detachably provided on the back surface of the body 101. A user may open the battery-mounting groove 119 by removing the cover member 102 as needed. In addition, the cover member 102 is provided with an opening 127 that exposes the camera module 117 so that a subject may be photographed even when the cover member 102 is coupled to the body 101.
A wireless charging module is provided on the inner surface of the cover member 102. The wireless charging module includes a receiving-side resonant antenna 131 and a receiving circuit unit. A second cover member 141 may be provided on the inner surface of the cover member 102 so as to provide a stable installment structure of the receiving-side resonant antenna 131 and the receiving circuit unit.
The receiving-side resonant antenna 131 produces signal power by a magnetic induction or magnetic resonance phenomenon, according to an electromagnetic field generated at a primary coil of a charger (not illustrated), and transmits the signal power to the receiving circuit unit. A connection piece 131a connected to the receiving circuit unit is formed at a side of the receiving-side resonance antenna 131, which may be attached on the inner surface of the cover member 102. In the portable terminal 100 illustrated in FIG. 1, however, the second cover member 141 is coupled to the cover member 102 when the receiving-side resonant antenna 131 is attached to the inner surface of the second cover member 141. As a result, the receiving-side resonant antenna 131 is disposed on the inner surface of the cover member 102.
Thus, the terminal 100 is provided with an electromagnetic shielding member 139 in order to cut off an electromagnetic field effect exerted on circuit devices inside the body or a battery pack, formed around the receiving-side resonance antenna 131. The electromagnetic shielding member 139 is attached on the cover member 102 and interposed between the receiving-side resonant antenna 131 and the body 101. Since the receiving-side resonant antenna 131 is directly attached to the second cover member 141, the receiving-side resonant antenna 131 may be attached on the electromagnetic shielding member 139 after the electromagnetic shielding member 139 is attached to the second cover member 141 in advance.
Since the receiving circuit unit includes the wireless charging circuit provided on the substrate 133, the receiving circuit unit converts signal power received through the receiving-side resonant antenna 131 into charging power, and provides the charging power to the battery pack mounted on the body 101. A connection portion 131b corresponding to the connection piece 131a is provided at a side of the substrate 133. The receiving circuit unit is also attached to the second cover member 141 together with the receiving-side resonant antenna 131. When the receiving-side resonant antenna 131 and the receiving circuit unit are attached to the second cover member 141, the connection piece 131a and the connection portion 131b are engaged with each other to be electrically connected.
A flexible printed circuit board 135 is disposed at a side of the receiving circuit unit and includes a connection pad 137 at one end. The charging power provided from the receiving circuit unit is transmitted to the body 101 through the flexible printed circuit board 135 and the connection pad 137. The body 101 is provided with connection terminals 115 at a side of the battery-mounting groove 119. When the cover member 102 is coupled to the body 101, the connection pad 137 is connected with the connection terminals 115, thereby providing the charging power to the body 101, in particular, to the battery pack mounted on the body 101.
FIG. 2 schematically illustrates a configuration of the wireless charging module disposed on the cover member 102. In FIG. 2, the height h of the wireless charging module, i.e. the thickness is illustrated. It is noted that the second cover member 141 is not illustrated in FIG. 2, and the wireless charging module is illustrated as being directly attachable to the cover member 102.
The receiving-side resonance antenna 131 and the electromagnetic shielding member 139 are stacked on the inner surface of the cover member 102. The receiving circuit unit includes circuit elements 133a such as a charging control circuit chip and an inductor, which are mounted on the substrate 133. The thicknesses of the receiving-side resonant antenna 131 and the substrate 133 are about 0.35 mm, the thickness of the electromagnetic shielding member 139 is about 0.6 mm, and the maximum height of the circuit elements 133a is about 1.25 mm. Accordingly, the maximum thickness of the wireless charging module from the inner surface of the cover member 102 is about 1.6 mm.
As described above, as multimedia functions of portable terminals have expanded, display devices have been enlarged and efforts have been made to reduce the thickness and weight of the portable terminals. A wireless charging module may enhance the convenience to charge a portable terminal but increases the thickness of the portable terminal. Particularly, slimmer portable terminals having a thickness of not more than 10 mm will have compromised size when equipped with a wireless charging module having a thickness of about 1.6 mm.