Display apparatus using diffraction unit

A display apparatus, comprising:

• an output unit to form an image and output it to the front;
• a lens unit disposed in front of the output unit to transmit the image to be output and transfer the image to the front;
• a guide unit formed to be long and having at least one pair of total reflection surfaces, a part of which is disposed between the output unit and the lens unit, in which a transmission path through which the illumination light incident from one side moves to the other side through at least one or more internal total reflections is formed;
• and
• a diffraction unit which is disposed on the transmission path and transmits the incident illumination light with a predetermined pattern to the output unit at a predetermined angle;
• wherein the diffraction unit selectively refracts or reflects the light corresponding to the characteristic of the incident illumination light to transmit the refracted or reflected light in a predetermined direction.