As a typical miniaturized smart device, the miniature projection system is an important part of a head-mounted display device. In the micro-projection system with a LCOS or a DMD as the display chip, the performance of the lighting system directly affects the final imaging quality. We design and simulate two lighting systems based on compound eyes and a diffuser respectively. The design shows that without considering the loss of polarized light the light energy utilization rate of the system based on compound eyes is 70.3% while that of the system based on a diffuser is 25%, and with the ANSI nine-point sampling method the calculated uniformity of the system based on compound eyes is 91%, while that of the system based on a diffuser is 88%, and the axial length of the lighting system based on the diffuser is 0.6 times that of the lighting system based on compound eyes. According to the analysis of design results, the compound eyes based system results in higher energy utilization and uniformity compared with a diffuser based one. Since the compound eyes based system needs a relay system, it nevertheless has a larger volume. Therefore, it is necessary to choose a suitable lighting method according to actual needs of a specific head-mounted display device.
In this paper, a micro-projection display with telecentric beam path in image space is designed. The device consists of a 0.26-inch liquid crystal on silicon (LCOS), a polarizing beam splitting cube and a hybrid refractive-diffractive eyepiece. The refractive-diffractive eyepiece has a focal length of 9.16 mm, a full field of view of 40° and a spectral bandwidth of 422~632 nm. The eyepiece is optimized by the wide-angle eyepiece, which consists of four optical lenses. The designed hybrid refractive-diffractive micro-projection display system has good projection effect while using a small number of lenses in a simple structure. This provides a reference for the future development of lightweight micro-projection systems.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.