Head mounted display and method for controlling the same

A head mounted display (HMD), comprising:

• a display;
• a body coupled to the display;
• a lens driving unit coupled to the body;
• and
• wherein the lens driving unit includes:
• a lens frame coupled to the body, wherein the lens frame includes a first tube portion and a plate that is formed at one side of the first tube portion, wherein the first tube portion protrudes from the plate, and wherein the first tube portion includes a central axis;
• a lens housing that includes a lens and a second tube portion, wherein the second tube portion includes an inner side that is shaped to overlap varying amounts of an outer side of the first tube portion, the second tube portion and the lens being positionable relative to the first tube portion in first and second directions that are each parallel to the central axis of the first tube portion;
• a link unit coupled to the lens frame;
• and
• a driving unit structurally coupled to the lens frame, to the second tube portion, and to the link unit, wherein the driving unit is configured to drive the link unit to cause the second tube portion and the lens to move linearly relative to the first tube portion in the first and second directions and vary an amount of the overlap of the inner side of the second tube portion relative to the outer side of the first tube portion.