Research On Technology Of Retinal Projection Display

Head-mounted display (HMD), which is widely used as modern digital military equipment, has already become necessary equipment in soldier's simulation training and actual combat, and it is also widely used in people's daily lives. Retinal projection display technology is a kind of HMD technology which has many advantages; People can observe projection information and real objects at the same time in the eye's accommodation. At present, there are some investigations on retinal projection display technology at home and abroad, but it hasn't form practical product. Because of using value is very high, this technology still needs further study.In this paper, current development trend and related research achievements of HMD are analyzed, and the principle of HMD is researched. The whole scheme of retinal projection display is determined, according to the principle of the retinal projection display. This system is designed by using the principle of the Maxwellian View, making the direct projection of a miniature SLM onto the user's retina in combination with the use of laser, because of the lights from each pixel pass through the center of crystalline lens, imaging being independent from the eye's accommodation. The optical system of the retinal projection display includes laser beam extender and filtering projection systems. Laser beam extender and filtering projection systems are designed with ZEMAX software respectively. Optical experiment of retinal projection display is carried out. Displaying function is tested and verified.In laser beam extender system, the entrance pupil diameter is 1.5mm, and extender multiple is 10. The value of MTF is above 0.8 on 120lp/mm. In filtering projection system, the focal length is-46.7mm, relative aperture is 1/2. The value of MTF in axial field of view on 120lp/mm is above 0.6. In experiment of optical principle, when changing CCD camera's focal length, the projection imaging is always clear on CCD with a resolution of 4320×3240. So the beam path of retinal projection displayer is feasible.