Timothy L. Wong

Folded optics with birefringent reflective polarizers

Polymeric, birefringent reflective polarizers have been used to produce compact, mid-field-of-view eyepieces and wide field-of-view optics for virtual reality (VR) head-mounted displays using the “pancake” lens configuration. Multiple configurations for pancake lens systems are discussed as are their advantages and disadvantages relative to refractive systems. Polarization control is an important consideration and the polarizing effects of different components are discussed. Designs for mid-FOV and wide FOV are presented and additional benefits of using folded optics for virtual reality systems are explored.

Efficient 3M PBS enhancing miniature projection optics

Over the past decade, 3M has developed a number of mobile projectors, with a goal towards providing the world’s smallest, most efficient projection systems. Compact size and efficiency are required characteristics for projection systems used in mobile devices and more lately, in augmented reality systems. In this paper we summarize the main generations of 3M light engine optical designs. We present the optical architectures of four light engines, including the rationale behind the illumination designs and the projection systems. In particular, we describe various configurations relating to the 3M polarizing beam splitter (PBS) which is key to enhanced efficiency of the miniature projection systems.