Head-mounted display

1. A head-mounted display comprising:

a pair of headphones having a built-in speaker for outputting sound;

a first arm rotatably coupled to the pair of headphones and displaying an image, the first arm having a band shape having a half-circular arc in cross section;

a second arm coupled to the pair of headphones to be relatively rotatable with the first arm to cover and release a front surface of the first arm, the second arm having a band shape having a half-circular arc in cross section;

a plurality of position detecting sensors sensing positions of the first arm and the second arm; and

a control unit controlling the image output to the first arm and the sound output to the headphones according to the sensing positions of the first arm and the second arm,

wherein the first arm is made of a transparent flexible display and the second arm is made of an opaque material such that an image displayed on the display of the first arm is viewed clearly when the second arm covers the first arm and

wherein the display of the first arm is divided into a left part and a right part.

2. The head-mounted display of claim 1 , wherein each of the first arm and the second arm reciprocally moves among a first position located on a front side of the head of a wearer, a second position located on an upper side of the head of the wearer, and a third position located on a rear side of the head of the wearer.

3. The head-mounted display of claim 2 , further comprising:

a data storage unit which stores an image data, a sound data, and an information data therein;

a camera shooting an image;

a microphone through which sound is input;

a display module for displaying an image on the first arm;

a sound output module for outputting sound through the speaker;

a mobile communication module for providing a smart phone function and enabling communication with an external apparatus; and

an operation unit for handling operations of the camera, the microphone, the display module, the sound output module, and the mobile communication module,

wherein the control unit controls the camera, the microphone, the display module, the sound output module, and the mobile communication module according to an operation signal of the operation unit.

4. The head-mounted display of claim 3 , comprising a risk sensing function and a warning function through the camera and the microphone.

5. The head-mounted display of claim 2 , wherein the control unit performs control operations to display the image data on the first arm, to output sound data through the speaker, and to communicate with an external apparatus through a smart phone function provided thereto when the first arm is located on the first position and the second arm is located on anyone of the first, the second, and the third position.

6. The head-mounted display of claim 2 , wherein the control unit performs control operations to display the image data on the first arm and simultaneously to output sound data through the speaker when the first arm and the second arm are located on the first position overlapping each other.

7. The head-mounted display of claim 2 , wherein the control unit performs control operations to output sound data through the speaker and to communicate with an external apparatus through a smart phone function provided thereto when the first arm and the second arm are located on the second position or the third position overlapping each other.

8. The head-mounted display of claim 1 , wherein the headphones comprise a first rail groove and a second rail groove spaced apart by a predetermined interval from each other such that the first arm and the second arm are able to rotate along rotation tracks of the first and second rail grooves, and the plurality of position detecting sensors are provided on the first rail groove and the second rail groove.

9. The head-mounted display of claim 1 , wherein a GPS module and a gyro sensor are provided to at least anyone of the headphones, the first arm, and the second arm.

10. The head-mounted display of claim 1 , wherein the first arm and the second arm rotate independently around the pair of headphones without rotation of the pair of headphones, such that each of the first arm and the second arm can be located on one of a first position located on a front side of the head of a wearer, a second position located on an upper side of the head of the wearer, and a third position located on a rear side of the head of the wearer.