Digital Head-mounted Display And Research On Its Critical Technology

Head-mounted display (HMD), which acts as an important role in augmented reality, virtual reality and stereoscopic presentation, is a new technique of modern display technology. As the high-resolution image reconstruction, holography and binary optics are developed, the optical design for HMD system breaks through the limitation.This paper firstly introduces the development of the HMD, and analyses some special requirements of airborne condition for display technology. Considering of human factors associated with HMD, researchers focus on field of view, exit pupil, resolution, displaying manner, eye relief and character color of HMD optical system, and set up system guideline of HMD which can give reference for later optical system design based on visor, which leads to a large exit pupil diameter and field view.Secondly, un-cooled Infrared Focal Plane Array (UFPA) of the infrared helmet is researched in the paper and proposes an algorithm of independent equations of pixel grey level, which can eliminate the aliasing effect caused by the sub-Nyquist sampling of UFPA imaging. The correspondence relationship of pixel grey level between the high-resolution image and the image sequence with low resolution is analyzed. The image sequence is acquired by displacing each time the image over the detector plane by a distance equal to half of the detector pitch. The independent equations of pixel grey level for high resolution image are set up, with which the high resolution image is reconstructed. The result of simulation show that this algorithm is exactly feasible and the time taken in reconstruction is shorten to milliseconds. It lays foundation for reconstructing high resolution video. Based on the theory and simulation, mechanical microscanning is proposed in the paper. The communication and reconstruction program are written in computer, and D/A conversion and communication program are written in the MCU. The circuit for amplifying the voltage form D/A convertor is design. Set up the experiment system, and analyze the reconstruction result.Thirdly, The phase and color dispersion are discussed in details. The design method of hybrid refractive/diffractive optical imaging system is analyzed. The refractive/diffractive ocular imaging system is brought to the head mounted display system. The ocular based on refractive/diffractive lens is designed in the paper. Compared with the Erfle ocular, the advantage of the new optical system is presented in the paper. The helmet optical system and its excellence based on the refractive/diffractive lens are also presented in the paper, which results in small configuration and light weight.