Patent ID: 12204166

MODE FOR THE INVENTION

Hereinafter, a lens driving apparatus according to an embodiment will be described with reference to accompanying drawings.FIG.1is an exploded perspective view showing the lens driving apparatus according to the embodiment,FIG.2is a sectional view showing the lens driving apparatus inFIG.1, andFIG.3is a perspective view showing a state in which a magnet and a coil are installed at the yoke inFIG.1.

As shown inFIGS.1and2, the lens driving apparatus according to the embodiment comprises a base110and a metal yoke120which are coupled to each other to form a predetermined space.

The base110has a disc shape or a polygonal plate shape and is formed at the central portion thereof with a through hole111. The bottom surface of the base110is coupled to an electronic appliance (not shown) and a circuit substrate112provided with an image sensor (not shown) is arranged in the through hole111.

The yoke120is coupled to the base110to serve as a case for protecting parts. The yoke120has an upper surface, at which a hole121allowing entrance of a lens module200is formed, an opened bottom surface making contact with the upper surface of the base110, and closed lateral side surfaces.

The side surfaces of the lens driving apparatus according to the embodiment are closed by the base110and the yoke120. Accordingly, since an additional case for protecting the lens driving apparatus is not necessary, the structure of the lens driving apparatus can be simplified. Further, since the side surfaces of the lens driving apparatus are closed, external impurities cannot penetrate into the inner side of the lens driving apparatus.

A ring-shaped bobbin130that goes in and out the hole121is movably installed at the inner side of the yoke120. The lens module200provided with a lens202and a support201for supporting the lens202is coupled to the inner peripheral surface of the bobbin130.

The bobbin130includes an outer surface having a circular or a polygonal shape corresponding to the yoke120, and an inner surface having a circular shape corresponding to the outer surface of the lens module200. According to the embodiment, the bobbin130includes an outer surface having an octagonal shape.

Magnets140are fixed to the inner peripheral surface of the yoke120, and a coil150is wound around the outer peripheral surface of the bobbin130while facing the magnets140.

The magnet140has a circular or a polygonal shape corresponding to the yoke120. As shown inFIGS.1and3, when the yoke120is a polygonal case, a plurality of prism magnets140are prepared and three sides of each magnet140make contact with the inner peripheral surface of the yoke120.

In the lens driving apparatus according to the embodiment, since the magnets140are installed at four edges of the yoke120, respectively, an empty space between the yoke120and the coil150can be effectively utilized. Accordingly, the lens driving apparatus can be manufactured in a smaller size. Further, since the prism magnet140is inexpensive as compared with a ring-shaped magnet, the lens driving apparatus with a low price can be manufactured.

Since the coil150is wound around the outer peripheral surface of the bobbin130, the coil150has a circular or a polygonal shape corresponding to the outer surface of the bobbin130. If the coil150has a polygonal shape and the magnet140has a circular shape, the distance between the coil150and the magnet140becomes non-uniform.

Accordingly, when the coil150has a polygonal shape, the magnet140has a prism shape as shown inFIGS.1and3.

As electric current is applied to the coil150, the coil150moves upward according to the interaction of the electric field generated by the coil150and the magnetic field generated by the magnet140, and thus the bobbin130moves upward. Accordingly, the lens module200coupled to the bobbin130also moves upward.

In addition, if the electric current is not applied to the coil150, the bobbin130moves downward. To this end, upper and lower leaf springs161and165having a coil structure are installed at the upper and lower portions of the bobbin130in order to provide restoration force for returning the bobbin130to the initial state.

At this time, the outer portion of the upper spring161is inserted between the yoke120and the upper surface of the magnet140. Further, the inner portion of the upper spring161is inserted into first support protrusions131formed on the upper end surface of the bobbin130. Accordingly, the upper spring161can be inhibited from being rotated and moved due to external impact.

The inner portion of the lower spring165is integrally formed with the bobbin130through injection molding, and the outer portion of the lower spring165is inserted between the bottom surface of a spacer170and the base110. Further, second support protrusions133that make contact with the inner peripheral surface of the through hole110formed in the base110are formed on the lower end surface of the bobbin130. The second support protrusions133guide and support the bobbin130such that the bobbin130can be coupled to another element at an exact position and exactly move upward and downward.

The spacer170is installed at the base110below the magnets140and the outer surface of the lower spring165is inserted between the lower surface of the spacer170and the base110. That is, the outer portion of the lower spring165is supported between the spacer170and the base110, and the inner portion of the lower spring165is integrally formed with the bobbin130, so that the lower spring165can be inhibited from being rotated and moved due to external impact.

Further, the spacer170has insertion protrusions171used for firm coupling and movement prevention of the spacer170, and the base110has support holes173into which the insertion protrusions171are inserted.

The yoke120and the spacer170have step sections120aand170a, respectively, as shown inFIG.2. the step sections120aand170aprovide a space for movement of the middle parts of the upper and lower leaf springs161and165.

Hereinafter, a coupling structure of the base110and the yoke120will be described with reference toFIGS.1,2and4.

FIG.4is a perspective view showing a coupling state of the yoke and the base inFIG.1.

As shown inFIG.4, the base110has a plurality of protrusion plates115protruding upward on the outer surface thereof, and locking protrusions117are formed at the protrusion plates115, respectively. Further, the yoke120has locking holes127at the sides thereof, into which the locking protrusions117are inserted.

The base110is closely coupled to the yoke120by using the locking protrusions117and the locking holes127.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure.

INDUSTRIAL APPLICABILITY

The lens driving apparatus according to the embodiment can be manufactured in a small size, can inhibit external impurities from penetrating into the inner portion of the lens driving apparatus, and is not broken due to external impact.

Further, the lens driving apparatus according to the embodiment can be applied to both cameras and various electronic appliances provided with the cameras.