Design of freeform surface optical component in helmet mounted display6 views
Keywords:Helmet display; Optics freeform; Surface; Optical design.
Helmet display (HMD) is the core hardware of virtual display technology. It is a small display device mounted on the helmet to produce visual images for the user. The MHD system mainly consists of an image source, optical, and support system. Still, the traditional optical subsystem cannot achieve the functions of the ideal optical system, such as being light-weight, small in size, and having an extensive field angle. This paper established the proper initial model, and the optimal control conditions and surface upgrade strategy were determined. Herein, the design scheme of the free-form prism with good performance was obtained. We solve the feature of large volume and complicated structure of optical components of helmet display and describe the design idea of free-form prism in detail. In this paper, the system resolution we designed is 800 × 600, the Modulation transfer function (MTF) value of the prism is more significant than 0.1 at the spatial resolution of 30 lp/mm, and the distortion is less than 5%. The exit pupil diameter of the system is 8 mm, and the field angle is 26°×20°.
. Peter Ott. "Optic design of head-up displays with freeform surfaces specified by NURBS". [J]. SPIE . (2008).
. Takahisa Ando. "Head mounted display using holographic optical element" [C]//Proc. SPIE, 3293:183-189, , (2003)
. Shoichi Yamazaki, Kazutaka Inoguchi, Yoshihiro Saito. "A Thin, wide-field-of-view HMD with free-form-surface prism and applications" [C]//Proe. SPIE, 3639:453-462, (1999) DOI: https://doi.org/10.1117/12.349411
. Gao Yong, Zhou Hai-xian, Zhao Zhi-min, "Study On HMD optical system" [J]．Electronics Optics&Control, 9(3):37-40, (2002).
. M. M. Talha, Yongtian Wang, Dewen Cheng, "Design of a Compact Wide Field of View HMD Optical System using Freeform Surfaces", [J]. SPIE. (2007) DOI: https://doi.org/10.1117/12.791113
. Hiroaki Hoshi, Naosato Taniguchi, Hideki Morishima, "Off-axial HMD optical system consisting of aspherical surfaces without rotational symmetry". [J].Proceedings of SPIE, 3653:234-242, (1996). DOI: https://doi.org/10.1117/12.237443
. M.M. Talha, Jun Chang, Yongtian Wang, "Design, tolerancing and stray light analyses of a freeform HMD optical system", Science Direct, Optical.11, 750 – 755, (2010). DOI: https://doi.org/10.1016/j.ijleo.2008.11.005
. Dewen Cheng, Yongtian Wang, Hong Hua, "Large field-of-view and high resolution free-form head-mounted display", Proc. SPIE, 13-18 Vol. 7652, 76520D_1-12, (2010).
. Brecher C, Lange S, Merz M, "NURBS based ultra-precision free-form machining". CIRP Annals, 59(1):547–550, (2006). DOI: https://doi.org/10.1016/S0007-8506(07)60479-X
. Brinksmeier E, Riemer O, Gla¨be R, "Submicron functional surfaces generated by diamond machining". CIRP Annals, 59(1):535–538, (2010). DOI: https://doi.org/10.1016/j.cirp.2010.03.037