Head-mounted display using holographic optical element

Abstract

We have been developing the stereoscopic display using the Holographic Optical Element(HOE) for applying the new Head Mounted Display(HMD). The HOE is the grating that is made by Holography technique. It has the interference :fringe by two-laser beam interference method and its optical fimction can provide us with the binocular parallax images. We have already developed two kinds of stereoscopic displays using HOEs, one is the new HMO using the diverging HOE, and another is the Retinal Projection Display using the converging HOE. In this report, we will introduce the concept and experimental prototype of these displays. First, we introduce the HOE which is very suitable for a combiner of the HMO. The only one piece of HOE recorded the interference fringe can separate the stereoscopic images onto each left and right eye. In addition, the visible rays through the HOE can be transparent with high intensity and the virtual images can be diffiacted with high efficiency. By using these optical characteristics of HOE, we accomplished the new HMO using the HOE that we can observe the real world with wide field of view and the virtual images with high intensity Second, we propose the Retinal Projection Display. We completed the new optical system using the converging HOE that has the feature of the Maxwellian View. We can see the virtual images without our ocular accommodation because the focal dep1h of the image is extremely deep. The coherent parallel laser rays modulated by the Spatial Light Modulator(LCD or DMD) are converged at the center of the aystalline lens and they are projected on the retina directly. Th.is condition is same as the case of pan focus. If this characteristic is applied to the binocular condition, it is very suitable for binocular parallax stereoscopic display because the problem of the dissociation between accommodation and convergence may be solved