Lens driving apparatus

A lens driving apparatus comprising:

• a base comprising an opening, wherein the base comprises an inner lateral surface at the opening;
• a yoke coupled to the base, the yoke having an upper plate formed with an opening, a closed side plate extending from an edge of the upper plate, wherein the upper plate and the closed side plate are monolithically formed;
• a bobbin disposed in the yoke and configured to move in a first direction along an optical axis, wherein the bobbin comprises a first support protrusion disposed on an upper surface thereof and a second support protrusion disposed on a lower surface thereof;
• four magnets fixed to an inner portion of the yoke;
• a coil wound around an outer peripheral surface of the bobbin while facing the four magnets;
• and
• springs coupled to the bobbin to provide restoration force to the bobbin,
• wherein the springs comprise an upper spring coupled to the upper surface of the bobbin and a lower spring coupled to the lower surface of the bobbin;
• wherein the coil has an octagonal shape including eight outer side surfaces, wherein four outer side surfaces of the eight outer side surfaces of the coil face the four magnets, respectively;
• wherein each of the four magnets has a prism shape comprising a lower surface, an upper surface, and side surfaces;
• wherein the side surfaces of each of the four magnets comprise a first flat plane facing the coil and three flat planes not facing the coil, and the coil comprises four flat planes respectively facing the first flat planes of the four magnets;
• wherein the four magnets are disposed at four corners of the yoke, respectively, such that the three flat planes of each magnet comprise a second flat plane, a third flat plane, and a fourth flat plane disposed between the second flat plane and the third flat plane and opposite to the first flat plane, an area of the first flat plane being greater than an area of the fourth flat plane;
• wherein the bobbin, the four magnets, the coil, the upper spring, and the lower spring are disposed within a space surrounded by the base and the yoke such that a first side of the upper spring is disposed between the yoke and the upper surface of the four magnets, a second side of the upper spring is coupled to the bobbin, and the first side of the upper spring is vertically overlapped with an inner surface of the upper plate of the yoke at the four corners of the yoke and is horizontally overlapped with the closed side plate of the yoke;
• and
• wherein the second support protrusion of the bobbin is inserted into the opening of the base such that the second support protrusion of the bobbin faces the inner lateral surface of the base and is configured to contact the inner lateral surface of the base.