The HMD optical system composed of "Free-Form-Surface prism (FFS prism)" was presented by Canon Inc. in 1995 [1-3]. This HMD is suitable for compact HMD. We have developed a new see-through 3D HMD with high resolution, wide field of view (FOV) by improving this FFS prism technique. The new HMD with 51degrees horizontal FOV and large viewing eyebox shows clear full color image (VGA) with 920,000 pixels. In spite of the wide FOV, the thickness of this new FFS prism is very thin, 17.9mm. In this paper, we report this new HMD and "the AR^2hockey system" as an example of this HMD application.
