High luminance and high see‐through head‐mounted displays with beam‐splitter‐array waveguides

Abstract

We have developed head‐mounted displays with high transmittance and luminance, which could be utilized outside safely without dimming glasses. We first specified required optical performance specifications by considering user's safety and usability. In order to ensure that the user is able to recognize both surrounding environment and the image of the head‐mounted display, we set the target specification that the transmittance is higher than or equal to 85%, and the luminance contrast ratio is larger than or equal to 1.15 with display image of white solid pattern. We then developed the beam‐splitter‐array waveguide to achieve the requirements. It has advantages in high efficiency and high see‐through property. In order to determine configuration of the waveguide, we have performed optical ray trace simulation. We also established versatile waveguide measurement method applicable to different‐type waveguides. By utilizing the waveguide we have developed, we made a prototype of a head‐mounted display (HMD) with high transmittance 94% and high luminance 4.8 × 103 cd/m2 and thus luminance contrast ratio 1.25 under the sun. With these advantages, our HMD is suitable for usage outside including applications of work support systems where dimming effect is not preferred, and the HMD is used under the sun.

Holographic waveguide display with large field of view based on volume holographic grating

“…7 The coupling elements, as the core of optical waveguides, play a crucial role in the imaging quality, such as FOV, optical efficiency and clarity. As coupling elements in optical waveguides, partial mirror arrays (PRMA), 8 polarization volume gratings (PVG), [9][10][11][12] volume holographic gratings (VHG), 13,14 and surface relief gratings (SRG) 15 are the applied solutions. Among them, the manufacturing process of PRMA requires very high precision, resulting in low production yields.…”

Determining Work-Rest Schedules for Visual Tasks That Use Optical Head-Mounted Displays Based on Visual Fatigue and Visually Induced Motion Sickness Recovery

“…The eyepiece magnifies a digital image from the microdisplay and forms an AR image that appears at a distance from the eye. The combiner superimposes the AR image of the OHMD on a real-world scene [1,2]. There are two common AR image presentation types in OHMDs: the screen-fixed type, where the AR image is displayed at a fixed position on the OHMD display screen, and the world-fixed type, where the AR image is displayed at a fixed position in a real-world environment [3,4].…”