Wavelength multiplexed field of view expansion for high-resolution near-to-eye displays

Abstract

We demonstrate a hologram-based image projector that expands the field of view (FOV) via wavelength multiplexing while retaining the flexibility of the high-resolution image displayed by a Digital Micromirror Device (DMD). Current Near-to-Eye Displays (NED) for AR/VR/MR applications are often limited in Etendue of the display devices and of the image transfer optics. Moreover, angular resolution and FOV are typically coupled, therefore a large physical package volume is also needed for large FOV optics. Our group previously reported increasing Etendue by custom pulsed illumination sources synchronized to a single DMD. To effectively utilize the increased Etendue along with the often angularly band-limited optical channels, for example, a TIR image guide, additional means to effectively increase Etendue of image transfer medium is needed. To address this challenge, wavelength multiplexed image transfer with extraction volume holograms proved to effectively increase the FOV at least by factor of 2. Along with the volume hologram, the prototype projector system employed 100ns pulsed dual lasers as sources, with a 0.7” DMD operating at 20kHz, coupled with a reflection type extraction volume hologram. In this talk, we address the optical architecture of wavelength multiplexed and FOV expanded projector, and are undergoing quantitative assessments of image quality, such as uniformity, resolution, contrast, and crosstalk.