Design Of Compact See-through Video Classes Optical System

Video glasses display is an emerging technology in the contemporary display field. With the rapid development of virtual reality and augmented reality technology, and the need of informationization forces, video glasses display has become more and more important, and has been widely used in many fields. In recent years, the see-through video glasses system has obtained a great achievement and becomes the top priority in the wearable display field.Based on the basic principle of the see-through video glasses display optical system, this thesis proposes a new cascaded optical waveguide combiner. We offer a complete design solution for compact see-through video glasses, which could be applied to consumer electronics application.Firstly, this thesis conducts a detailed study on see-through optical combiners. From the parameters of thickness, eye motion box and FOV, the features of curved mirror and waveguide optical combiner are compared. Based on this, waveguide optical combiner is studied; Furthermore, the relationship between FOV and waveguide structure is presented, the structure of the optical system is determined.To eliminate the ghost images of the semitransparent waveguide, a cascaded optical waveguide having a special reflective film is designed. From the design point of the reflection film, the reflection surface angle of the waveguide is studied. Secondly, the relationship between thickness of waveguide, number of reflection surface and FOV is given. The effective aperture of a single reflection surface and the distance of adjacent reflection surfaces are analyzed.Finally, illumination and eyepiece system are optimized, the illumination system can achieve19%energy efficiency and92.3%uniformity. Considering MTF, spot diagram, field curvature, distortion and lateral color, eyepiece system is analyzed.Based on the above design method, a compact see-through video glasses is fabricated and it’s performance is measured. The final parameters of the see-through video glasses are listed as follows:LCoS microdisplay resolution:852×480, the total weight of optical system:135g. Within a20mm exit pupil distance and8mm×8mm eye motion box, system can achieve30°FOV, under the drive circuit power consumption of1W, the brightness of the display is3000nit.