US Patent 9851091 Head mounted display

Disclosed is a head mounted display (HMD) having light emitting devices. The HMD includes a body having a plurality of surfaces; and a plurality of light emitting units formed on the plurality of surfaces and configured to emit light to outside of the body, wherein each of the plurality of light emitting units includes at least four light emitting devices that are disposed in a straight line in a spaced manner such that a specific cross ratio defines spacing for each of the plurality of light emitting units, a cross ratio of one of the plurality of light emitting units being different from cross ratios of other light emitting units among the plurality of light emitting units.