Digital Phase Conjugation by Texas Instruments PLM for Near-to-Eye Display

An ideal Near-to-Eye display (NED) requires high-resolution images, a large field of view (FOV) and depth cues. Sometimes, those performances are degraded due to optical aberrations of optics. To correct for aberrations, in this work, we utilize digital phase conjugation (DPC) with a Texas Instruments phase light modulator (TI-PLM) to generate a 3D image with TIR/geometrical image guide. TI-PLM is a type of MEMS device that modulates the phase of the incoming light by moving the micromirrors in a piston motion, thereby modulating the phase. To measure aberration induced by the image guide combiner, we employed an off-axis holography, capturing the off-axis fringes using a camera sensor. Subsequently, image processing on the captured fringes, involving Fourier transform and cropping of +1st order, to extract the final field information while reducing low-frequency noise. Computer-generated hologram (CGH) was generated to negate the phase aberration, which is then displayed on the PLM. Through phase conjugation, we reconstruct the wavefront, resulting in a series of point sources displayed at different depths, and producing a 3D point images. This method allows us to generate multiple point sources with different depths, contributing to the 3D image in our Near-to-Eye display even via aberrated medium.