Abstract: This paper introduces the concept, invention and work principle of HUD (head up display). The application situation of HUD equipment in field of avigation, motorcar and the like is introduced, and the development trend and key technology of HUD equipment is analyzed. The application of HUD technology will become more and more extensive, with the continuous improvement of drive quality and security requirement and rapid development of smart equipment.

Key words: head up display, airplane cockpit display system, wearable device